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