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