#!/usr/bin/env python2
# -*- coding: utf-8 -*-

import sys

def suma(liczby):
    suma_liczb = 0
    for i in liczby:
        try:
            suma_liczb += float(i)
        except:
            suma_liczb += 0
    return suma_liczb

def main():
    print(suma([1, 2, 3, 4]))

if __name__ == "__main__":
    main()
else:
    suma(sys.argv[1:])