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