#include <bits/stdc++.h>
using namespace std;
int main() {
  string s1, s2, s3;
  cin >> s1 >> s2 >> s3;
  string str;
  str = s1 + s2;
  sort(str.begin(), str.end());
  sort(s3.begin(), s3.end());
  if (s3 == str) {
    cout << "YES" << endl;
  } else
    cout << "NO" << endl;
}
