#include<bits/stdc++.h>
#define _LIBCPP_DEBUG 0
using namespace std;
typedef long long int ll;
ll MOD = 1e9 + 7;
int INF = 1 << 30;


int main(void){

    string A,B; cin>>A>>B;
    ll size = max(A.length(), B.length());
    for (ll i = 0; i < size; ++i) {
        cout<<((A[i]-'0') ^ (B[i]-'0'));
    }
    cout<<endl;
    return 0;
}