#!/usr/bin/env python3

import os

print("Content-Type: text/plain; charset=utf-8")
print()

s = os.environ.get("QUERY_STRING", "")

try:
    if "+" in s:
        a, b = s.split("+", 1)
    elif "%2B" in s.upper():
        # 后面再正规处理
        raise ValueError

    print(int(a) + int(b))
except:
    print("usage: /calc?114514+1919810")