diff --git a/TMI-practicum/Circle.cs b/TMI-practicum/Circle.cs
new file mode 100644
index 0000000..5c4091b
--- /dev/null
+++ b/TMI-practicum/Circle.cs
@@ -0,0 +1,23 @@
+using System;
+
+namespace TMI_practicum
+{
+    public class Circle
+    {
+        public readonly double X;
+        public readonly double Y;
+        public readonly double R;
+
+        public Circle(double x, double y, double r)
+        {
+            X = x;
+            Y = y;
+            R = r;
+        }
+
+        public double Distance(Circle otherCircle)
+        {
+            return Math.Sqrt(Math.Pow(X - otherCircle.X, 2) + Math.Pow(Y - otherCircle.Y, 2));
+        }
+    }
+}
\ No newline at end of file
diff --git a/TMI-practicum/Intersection.cs b/TMI-practicum/Intersection.cs
new file mode 100644
index 0000000..43382a6
--- /dev/null
+++ b/TMI-practicum/Intersection.cs
@@ -0,0 +1,14 @@
+namespace TMI_practicum
+{
+    public struct Intersection
+    {
+        public readonly double X;
+        public readonly double Y;
+
+        public Intersection(double x, double y)
+        {
+            X = x;
+            Y = y;
+        }
+    }
+}
\ No newline at end of file
diff --git a/TMI-practicum/Program.cs b/TMI-practicum/Program.cs
index 29da9eb..79df9c6 100644
--- a/TMI-practicum/Program.cs
+++ b/TMI-practicum/Program.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Diagnostics;
 using System.IO;
 using System.Linq;
 
@@ -20,10 +21,33 @@ namespace TMI_practicum
                 Console.WriteLine("File {0} not found.", args[0]);
                 Environment.Exit(1);
             }
+
+            var parsed = ParseFile(args[0]);
+            
+            IEnumerable<Intersection> solved;
+            
+            Stopwatch stopwatch = new Stopwatch();
+            stopwatch.Start();
+            
+            switch (parsed.Item1)
+            {
+                case 1:
+                    solved = SimpleAlgorithm.Solve(parsed.Item3);
+                    break;
+                case 2:
+                    throw new NotImplementedException();
+                case 3:
+                    throw new NotImplementedException();
+                default:
+                    throw new ArgumentException("Algorithm with id: " + parsed.Item1 + " is not defined!");
+            }
+            
+            stopwatch.Stop();
+            WriteOutput(solved, stopwatch.ElapsedMilliseconds / 1000.0);
         }
 
 
-        private static Tuple<byte, int, ICollection<Circle>> ParseFile(string path)
+        private static Tuple<byte, int, IList<Circle>> ParseFile(string path)
         {
 
             byte algoritm = 0;
@@ -52,10 +76,10 @@ namespace TMI_practicum
                 }
             }
             
-            return new Tuple<byte, int, ICollection<Circle>>(algoritm, nbCircles, circles);
+            return new Tuple<byte, int, IList<Circle>>(algoritm, nbCircles, circles);
         }
 
-        private static readonly string OutputFile = "output.txt";
+        private const string OutputFile = "output.txt";
 
         private static void WriteOutput(IEnumerable<Intersection> intersections, double time)
         {
@@ -70,34 +94,9 @@ namespace TMI_practicum
                 {
                     sw.WriteLine("{0}\t{1}", intersection.X, intersection.Y);
                 }
+
                 sw.WriteLine("\r\n{0}", time);
             }
         }
-
-        private struct Circle
-        {
-            public readonly double X;
-            public readonly double Y;
-            public readonly double R;
-
-            public Circle(double x, double y, double r)
-            {
-                X = x;
-                Y = y;
-                R = r;
-            }
-        }
-
-        private struct Intersection
-        {
-            public readonly double X;
-            public readonly double Y;
-
-            public Intersection(double x, double y)
-            {
-                X = x;
-                Y = y;
-            }
-        }
     }
 }
\ No newline at end of file
diff --git a/TMI-practicum/SimpleAlgorithm.cs b/TMI-practicum/SimpleAlgorithm.cs
new file mode 100644
index 0000000..65ccc4d
--- /dev/null
+++ b/TMI-practicum/SimpleAlgorithm.cs
@@ -0,0 +1,49 @@
+using System;
+using System.Collections.Generic;
+
+namespace TMI_practicum
+{
+    public static class SimpleAlgorithm
+    {
+        public static IEnumerable<Intersection> Solve(IList<Circle> circles)
+        {
+            var intersections = new Stack<Intersection>();
+
+            for (int i = 0; i < circles.Count - 1; i++)
+            {
+                for (int j = i + 1; j < circles.Count; j++)
+                {
+                    var c1 = circles[i];
+                    var c2 = circles[j];
+                    CalculateIntersection(intersections, c1, c2);
+                }
+            }
+
+            return intersections;
+        }
+
+        private static void CalculateIntersection(Stack<Intersection> intersections, Circle c1, Circle c2)
+        {
+            double d = c1.Distance(c2);
+            if (d > c1.R + c2.R || d < Math.Abs(c1.R - c2.R)) return;
+
+            if (d == 0.0 && c1.R - c2.R == 0.0) throw new ArgumentException("Circles may not be coincident!");
+            
+            double a = (c1.R * c1.R - c2.R * c2.R + d * d) / (2.0*d);
+            double px = c1.X + a * (c2.X - c1.X) / d;
+            double py = c1.Y + a * (c2.Y - c1.Y) / d;
+
+            double htemp = c1.R * c1.R - a * a;
+            if (htemp == 0)
+            {
+                intersections.Push(new Intersection(px, py));
+            }
+            else
+            {
+                double h = Math.Sqrt(htemp);
+                intersections.Push(new Intersection(px + h * (c2.Y - c1.Y) / d, py - h * (c2.X - c1.X) / d));
+                intersections.Push(new Intersection(px - h * (c2.Y - c1.Y) / d, py + h * (c2.X - c1.X) / d));
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/TMI-practicum/TMI-practicum.csproj b/TMI-practicum/TMI-practicum.csproj
index 41368d9..844d10a 100644
--- a/TMI-practicum/TMI-practicum.csproj
+++ b/TMI-practicum/TMI-practicum.csproj
@@ -40,8 +40,11 @@
     <Reference Include="System.Xml" />
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="Circle.cs" />
+    <Compile Include="Intersection.cs" />
     <Compile Include="Program.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
+    <Compile Include="SimpleAlgorithm.cs" />
   </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it.