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