#include <bits/stdc++.h>
using namespace std;
#include <atcoder/all>
using namespace atcoder;
template<typename T> inline bool chmax(T &a, T b) { return ((a < b) ? (a = b, true) : (false)); }
template<typename T> inline bool chmin(T &a, T b) { return ((a > b) ? (a = b, true) : (false)); }
#define rep(i, n) for (long long i = 0; i < (long long)(n); i++)
#define rep2(i, m ,n) for (int i = (m); i < (long long)(n); i++)
#define REP(i, n) for (long long i = 1; i < (long long)(n); i++)
typedef long long ll;

int main() {
 string s;cin>>s;
 string t;cin>>t;
 if(s.size()<t.size()){swap(s,t);}
 rep(i,t.size()){
 s[s.size()-i-1] = (char)(((s[s.size()-i-1]-'0'+t[t.size()-i-1]-'0')%2)+'0'); 	
 }
 cout << stol(s,nullptr,2) << endl;
}