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