diff --git a/echo.go b/echo.go
new file mode 100644
index 0000000..808216e
--- /dev/null
+++ b/echo.go
@@ -0,0 +1,49 @@
+package main
+
+import (
+"net"
+"os"
+"fmt"
+)
+
+type EchoServer struct {
+	port uint16
+}
+
+func NewEchoServer(port uint16) *EchoServer {
+	return &EchoServer{port}
+}
+
+func (s *EchoServer) Run() {
+	addr := fmt.Sprintf("0.0.0.0:%d", s.port)
+	server, err := net.Listen("tcp", addr)
+    if err != nil {
+      fmt.Println("Error listening:", err.Error())
+        os.Exit(1)
+    }
+    defer server.Close()
+    fmt.Println("EchoServer waiting for client...")
+    for {
+      connection, err := server.Accept()
+      if err != nil {
+        fmt.Println("Error accepting: ", err.Error())
+        os.Exit(1)
+      }
+      fmt.Println("client connected")
+      go s.processClient(connection)
+		}
+}
+
+func (s *EchoServer) processClient(connection net.Conn) {
+	buffer := make([]byte, 1024)
+	for {
+	  mLen, err := connection.Read(buffer)
+	  if err != nil {
+	    fmt.Println("Error reading:", err.Error())
+			break
+	  }
+	  fmt.Printf("Received %d bytes\n", mLen)
+	  _, err = connection.Write([]byte(buffer[:mLen]))
+	}
+  connection.Close()
+}
\ No newline at end of file
diff --git a/main.go b/main.go
index 7686d7f..d340dfa 100644
--- a/main.go
+++ b/main.go
@@ -1,7 +1,32 @@
 package main
 
-import "fmt"
+import (
+  "fmt"
+	"flag"
+	"os"
+)
 
+type Server interface {
+	Run()
+}
+	
 func main() {
-  fmt.Println("hello world")
+	var challenge int
+	flag.IntVar(&challenge, "challenge",1, "Challenge number")
+	flag.Parse()
+	
+	var port uint16 
+  port =	13370
+	var server Server
+  switch challenge {
+	  case 0:
+	  	server = NewEchoServer(port);
+		case 1:
+	  	server = NewPrimeServer(port);
+		default:
+			fmt.Printf("Unknown challenge\n")
+			os.Exit(1)
+		}
+	
+  server.Run()
 }
\ No newline at end of file
diff --git a/prime.go b/prime.go
new file mode 100644
index 0000000..0b79798
--- /dev/null
+++ b/prime.go
@@ -0,0 +1,49 @@
+package main
+
+import (
+"net"
+"os"
+"fmt"
+)
+
+type PrimeServer struct {
+	port uint16
+}
+
+func NewPrimeServer(port uint16) *PrimeServer {
+	return &PrimeServer{port}
+}
+
+func (s *PrimeServer) Run() {
+	addr := fmt.Sprintf("0.0.0.0:%d", s.port)
+	server, err := net.Listen("tcp", addr)
+    if err != nil {
+      fmt.Println("Error listening:", err.Error())
+        os.Exit(1)
+    }
+    defer server.Close()
+    fmt.Println("PrimeServer waiting for client...")
+    for {
+      connection, err := server.Accept()
+      if err != nil {
+        fmt.Println("Error accepting: ", err.Error())
+        os.Exit(1)
+      }
+      fmt.Println("client connected")
+      go s.processClient(connection)
+		}
+}
+
+func (s *PrimeServer) processClient(connection net.Conn) {
+	buffer := make([]byte, 1024)
+	for {
+	  mLen, err := connection.Read(buffer)
+	  if err != nil {
+	    fmt.Println("Error reading:", err.Error())
+			break
+	  }
+	  fmt.Printf("Received %d bytes\n", mLen)
+	  _, err = connection.Write([]byte(buffer[:mLen]))
+	}
+  connection.Close()
+}
\ No newline at end of file