#include <bits/stdc++.h>
using namespace std;
int main() {
  string str1, str2, str3, str4;
  cin >> str1 >> str2 >> str3;
  sort(str3.begin(), str3.end());
  str4 = str1 + str2;
  sort(str4.begin(), str4.end());
  if (str4 == str3)
    cout << "YES";
  else
    cout << "NO";
  return 0;
}
