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