import re
import sys


def main():
    print(str(validate(input("IPv4 Address: ").strip())))


def validate(ip):
    regex8 = re.compile(r'^((?:[0-9]\.|1?[0-9][0-9]\.|2[0-4][0-9]\.|25[0-5]\.){3}(25[0-5]|2[0-4][0-9]|1?[0-9][0-9]|[0-9]))$')
    ok = regex8.search(ip)
    if ok != None:
        return True
    else:
        return False

if __name__ == "__main__":
    main()