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