#include <bits/stdc++.h>
using namespace std;
int main() {
  char a[10000], b[10000];
  cin >> a;
  cin >> b;
  int k;
  k = strlen(a);
  for (int i = 0; i < k; i++) {
    if (a[i] == b[i])
      cout << 0;
    else
      cout << 1;
  }
}
