bitop1

/*
 Author: 曹北健(37509)
 Result: AC Submission_id: 4365351
 Created at: Wed Apr 20 2022 19:09:14 GMT+0800 (China Standard Time)
 Problem: 5594  Time: 11    Memory: 1628
*/

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <string.h>
#include <ctype.h>
#include <time.h>
#pragma warning(disable:4996)
typedef long long LL;
typedef unsigned long long ULL;
#define GETBIT64(x,i) ((long long)(x)>>(long long)(i))&1ll
LL gcd(LL a, LL b){
    return a % b ? gcd(b, a % b) : b;
}
int main(){
#ifdef _DEBUG
    FILE *fp = freopen("../../../input.txt", "r", stdin);
    //FILE *fp2 = freopen("output.txt", "w", stdout);
#endif // _DEBUG
    LL a, b, x1, x2, i, ans = 0;
    while(~scanf("%lld%lld", &a, &b)){
        ans = 0;
        for(i = 0; i < 64; i++){
            x1 = GETBIT64(a, i);
            x2 = GETBIT64(b, i);
            if(!((!x1) && x2)){
                ans |= (1ll << i);
            }
        }
        printf("%lld\n", ans);
    }
#ifdef _DEBUG
    freopen("CON", "r", stdin);
    //freopen("CON", "w", stdout);
    system("pause");
#endif // _DEBUG
    return 0;
}