#!/usr/bin/python3

import sys
import re

def error(port_range):
    print(f'Error: {port_range} is not a valid port or port range')
    sys.exit(1)

if __name__ == '__main__':
    if len(sys.argv)>1:
        port_range = sys.argv[1]
        if re.match('^[0-9]{1,5}-[0-9]{1,5}$', port_range):
            port_1, port_2 = port_range.split('-')
            if int(port_1) not in range(1, 65535) or int(port_2) not in range(1, 65535):
                error(port_range)
            if int(port_1) > int(port_2):
                error(port_range)
        elif not port_range.isnumeric() or int(port_range) not in range(1, 65535):
                error(port_range)
    else:
        sys.exit(2)

    sys.exit(0)