package main

import (
	"bufio"
	"fmt"
	"log"
	"net"
)

func handleConn(conn net.Conn) {
	defer conn.Close()
	scn := bufio.NewScanner(conn)
	for scn.Scan() {
		line := scn.Text()
		bs := []byte(line)
		result := make([]byte, len(bs))
		for i, v := range bs {
			if v <= 'z' && v >= 'a' {
				result[i] = v + 13
				if result[i] > 'z' {
					result[i] -= 26
				}
			} else if v <= 'Z' && v >= 'A' {
				result[i] = v + 13
				if result[i] > 'Z' {
					result[i] -= 26
				}
			} else {
				result[i] = v
			}
		}
		fmt.Fprintf(conn, "%s\n%s\n", result, bs)
	}
}

func main() {
	server, err := net.Listen("tcp", ":9000")
	if err != nil {
		log.Fatalln(err.Error())
	}
	defer server.Close()

	for {
		conn, err := server.Accept()
		if err != nil {
			log.Fatalln(err.Error())
		}
		go handleConn(conn)
	}
}