#include using namespace std; typedef long long ll; typedef vector vll; typedef vector vvll; typedef pair P; typedef string str; typedef vector

vp; typedef vector vs; typedef vector vb; const ll mod=1e9+7; const ll inf=1e16; #define rep(i,m,n) for(ll i=m;i=n;i--) #define fi first #define se second #define chmax(x,y) x=max(x,y) #define chmin(x,y) x=min(x,y) #define eb(x) emplace_back(x) #define pb(x) pop_back(x) #define all(x) x.begin(),x.end() #define allr(x) x.rbegin(),x.rend() #define sum(x) accumulate(all(x),0) #define pc(x) __builtin_popcount(x) #define gll greater() void solve(){ ll a,c; cin >> a>>c; cout << (a^c) << endl; } int main(){ cin.tie(nullptr); ios::sync_with_stdio(false); solve(); }