#include //#include"atcoder/all" #pragma GCC target("avx2") #pragma GCC optimize("O3") #pragma GCC optimize("unroll-loops") #define all(a) (a).begin(),(a).end() using namespace std; //using namespace atcoder; typedef long long ll; int main(){ ll a,c;cin >> a >> c; cout << (a^c) << "\n"; }