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