#!/usr/bin/python3
import sys, socket, errno
if len(sys.argv)>1:
	port = int(sys.argv[1])
else:
	port = 5900
    
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
while True:
    try:
        s.bind(("", port))
    except socket.error as e:
        if e.errno== errno.EADDRINUSE:
            port+=1
            continue
        else:
            raise e
    break

s.close()
print(port)
    
