#include <bits/stdc++.h>
using namespace std;
int main() {
  string x, y, z;
  cin >> x >> y >> z;
  string temp = x + y;
  sort(temp.begin(), temp.end());
  sort(z.begin(), z.end());
  z == temp ? cout << "YES\n" : cout << "NO\n";
  return 0;
}
