#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define all(v) begin(v), end(v)
using namespace std;
using P = pair<int,int>;
using ll = long long;
using vi = vector<int>;
using vll = vector<ll>;

int main() {
    int sum[31];
    rep(i,31) sum[i] = 0;
    string a,b;
    cin >> a >> b;
    
    rep(i,a.size()){
        sum[30-i] += a[a.size()-i-1] -'0';
    }
    
    rep(i,b.size()){
        sum[30-i] += b[b.size()-i-1] - '0';
        
    }
    
    for(int i = 30; i > 0; i--){
        if(sum[i] == 2) sum[i] = 0;
    }
    
    //rep(i,31) cout << sum[i];
    ll ans = 0;
    
    for(int i = 30;i >= 0;i--){
        ans += sum[i]*pow(2,30-i);
       }
    
    cout << ans <<endl;
    return 0;
}