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