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