#include <bits/stdc++.h>
int main() {
  char s1[100], s2[100], i, j, temp, s[100];
  scanf("%s", s1);
  int l1 = strlen(s1);
  scanf("%s", s2);
  int l2 = strlen(s2);
  scanf("%s", s);
  int l = strlen(s);
  if (l1 + l2 > l)
    printf("NO");
  else {
    for (i = 0; s1[i] != '\0'; ++i)
      ;
    for (j = 0; s2[j] != '\0'; ++j, ++i) {
      s1[i] = s2[j];
    }
    s1[i] = '\0';
    for (i = 0; i < l1 + l2 - 1; i++) {
      for (j = i + 1; j < l1 + l2; j++) {
        if (s1[i] > s1[j]) {
          temp = s1[i];
          s1[i] = s1[j];
          s1[j] = temp;
        }
      }
    }
    for (i = 0; i < l - 1; i++) {
      for (j = i + 1; j < l; j++) {
        if (s[i] > s[j]) {
          temp = s[i];
          s[i] = s[j];
          s[j] = temp;
        }
      }
    }
    int p = strcmp(s1, s);
    if (p == 0)
      printf("YES");
    else
      printf("NO");
  }
  return 0;
}
