#include <bits/stdc++.h>
int main() {
  std::string str1, str2, str3;
  std::cin >> str1 >> str2 >> str3;
  std::string str = str1 + str2;
  std::sort(str.begin(), str.end());
  std::sort(str3.begin(), str3.end());
  std::string out = str == str3 ? "YES" : "NO";
  std::cout << out;
  return 0;
}
