#include <stdio.h>

char *locatesubstr(char *str1, char *str2);
int main() {
  char str1[505], str2[505];
  char *p;
  // Was gets in the example, but it is unsafe.
  fgets(str1, 505, stdin);
  fgets(str2, 505, stdin);
  p = locatesubstr(str1, str2);

  if (p == NULL)
    printf("NULL!\n");
  else
    puts(p);

  return 0;
}

/* 请在这里填写答案 */
char *locatesubstr(char *str1, char *str2) {
  char *loc = NULL;
  int i;
  while (*str1 != '\0' && loc == NULL) {
    if (*str1 == *str2) { // Head matched
      loc = str1;
      i = 1;
      while (*(str2 + i) != '\0') {
        if (*(str1 + i) != *(str2 + i) &&
            *(str2 + i) != '\n' && // Because gets also inputs the \n
            *(str1 + i) != '\n') { // So we need to take care of that.
          loc = NULL;
          break;
        }
        i++;
      }
    }
    str1++;
  }
  return loc;
}