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