#include using namespace std; typedef long long ll; typedef long double ld; typedef pair l_l; typedef pair i_i; typedef vector vel; typedef vector vei; typedef vector vec; typedef vector veb; typedef vector ves; typedef vector> ve_vel; typedef vector> ve_vei; typedef vector> ve_vec; typedef vector> ve_veb; typedef vector> ve_ves; #define rep(i,n) for(int i=0;i<(int)(n);i++) #define rep1(i,n) for(int i=1;i<(int)(n);i++) #define rep2(i,n) for(int i=2;i<(int)(n);i++) #define repk(i,k,n) for(int i=k;i<(int)(n);i++) #define fs first #define sc second #define pub push_back #define pob pop_back #define all(a) a.begin(),a.end() #define rall(a) a.rbegin(),a.rend() #define maxel(a) *max_element(all(a)) #define minel(a) *min_element(all(a)) #define acc accumulate #define EPS (1e-7) //#define INF (1e9) #define PI (acos(-1)) #define mod (1000000007) typedef long long int64; const int64 INF = 1LL << 58; template bool chmax(T &a, const T &b) { if (a bool chmin(T &a, const T &b) { if (a>b) { a=b; return 1; } return 0; } int main(){ cin.tie(0); ios::sync_with_stdio(false); ll A, C; cin >> A >> C; ll B = A ^ C; cout << B << endl; }