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