#include <bits/stdc++.h>
using namespace std;
int main() {
  string a, b, c;
  char first[302];
  cin >> a >> b >> c;
  int i = 0;
  for (; i < a.size(); i++) first[i] = a[i];
  for (; i - a.size() < b.size(); i++) first[i] = b[i - a.size()];
  sort(first, first + a.size() + b.size());
  sort(c.begin(), c.end());
  for (i = 0; i < c.size(); i++)
    if (c[i] != first[i] || (a.size() + b.size()) != c.size()) {
      cout << "NO";
      return 0;
    }
  cout << "YES";
  return 0;
}
