#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (n); ++i)

int main(void)
{
  vector<int> b(9);
  rep(i, 9) cin >> b[i];

  vector<int> v(10);
  rep(i, 10) v[i] = i + 1;
  rep(i, 10) rep(j, 9) if (v[i] == b[j]) v[i] = 0;

  rep(i, 10) if (v[i] != 0) cout << v[i] << endl;
  return 0;
}