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