#include using namespace std; typedef long long ll; #define pb push_back #define fi first #define se second typedef pair P; using VP = vector

; using VVP = vector; using VI = vector; using VVI = vector; using VVVI = vector; const int inf=1e9+7; const ll INF=1LL<<61; const ll mod=1e9+7; template inline bool chmax(T &a, T b) { if(a < b) { a = b; return true; } return false; } template inline bool chmin(T &a, T b) { if(a > b) { a = b; return true; } return false; } int main(){ ios::sync_with_stdio(false); cin.tie(nullptr); int i,j; ll a,b; cin>>a>>b; cout<<(a^b)<