#include <bits/stdc++.h>
using namespace std;
int main() {
  string x, y, z, a;
  cin >> x >> y >> z;
  a = x + y;
  sort(a.begin(), a.end());
  sort(z.begin(), z.end());
  if (a == z)
    cout << "YES" << endl;
  else
    cout << "NO" << endl;
  return 0;
}
