#include <iostream>
using namespace std;

string a, b, c;

int main()
{
    cin >> a >> b;

    for(long long i = 0; i < a.size(); i++)
    {
        if(a[i] == '0' && b[i] == '1') c[i] = '1';
        if(a[i] == '1' && b[i] == '0') c[i] = '1';
        if(a[i] == '0' && b[i] == '0') c[i] = '0';
        if(a[i] == '1' && b[i] == '1') c[i] = '0';
    }

    for(long long i = 0; i < a.size(); i++)cout<<c[i];
}