#include <bits/stdc++.h>
using namespace std;
int main() {
  string x, y, z;
  cin >> x >> y >> z;
  int sumxy = x.length() + y.length();
  if (z.length() != sumxy) {
    cout << "NO" << endl;
  } else {
    bool c = true;
    string w = x + y;
    sort(w.begin(), w.end());
    sort(z.begin(), z.end());
    for (size_t i = 0; i < z.size(); i++) {
      if (w[i] != z[i]) {
        c = false;
        break;
      }
    }
    if (c == true)
      cout << "YES" << endl;
    else
      cout << "NO" << endl;
  }
  return 0;
}
