#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int i, j, k, sum = 0;
  char a[1000], b[1000];
  cin >> a >> b;
  for (i = 0; i < strlen(a); i++) {
    if (a[i] == b[i])
      cout << 0;
    else
      cout << 1;
  }
  cout << endl;
  return 0;
}
