UVa Soution 10469 : To Carry or not to Carry

#include<iostream>
#include<cstdio>
#include<cmath>
using namespace std;

int main()
{
    long long a, b;
    while(scanf("%lld%lld", &a, &b)==2)
    {
        printf("%lld\n", a^b);
    }
    return 0;
}