#include <bits/stdc++.h>
using namespace std;
int main() {
  string s1;
  string s2;
  string s3;
  cin >> s1 >> s2 >> s3;
  string s4 = s1 + s2;
  sort(s4.begin(), s4.end());
  sort(s3.begin(), s3.end());
  if (s4 == s3) {
    cout << "YES" << endl;
  } else {
    cout << "NO" << endl;
  }
  return 0;
}
