#include <bits/stdc++.h>
using namespace std;
int a[1005], b[1005], c[1005];
int main() {
  string s, p, q;
  while (cin >> s >> p) {
    int l;
    l = s.length();
    memset(a, 0, sizeof(a));
    for (int i = 0; i < l; i++) {
      b[i] = s[i] - '0';
      c[i] = p[i] - '0';
    }
    for (int i = 0; i < l; i++) {
      if (b[i] == c[i])
        a[i] = 0;
      else
        a[i] = 1;
    }
    for (int i = 0; i < l; i++) cout << a[i];
    cout << endl;
  }
  return 0;
}
