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