user_int.py

#!/usr/bin/env python
# -*- coding:utf-8 -*-
from __future__ import print_function
import sys

if sys.version_info.major < 3:
    input = raw_input

def main():
    while True:
        user_input = input("pleas enter a number: ")

        try:
            user_int = int(user_input)

            if user_int > 0:
                print("you just entered: {}".format(user_int))
            else:
                print("it is not a positive number")
        except ValueError:
            print("it is not a number")

if __name__ == "__main__":
    main()