#include <stdio.h>

int main(void) {
  int table[] = {461, 2771, 5081, 7391, 9701, 12011};
  int n;
  scanf("%i", &n);

  for (int i = 0; i < sizeof(table) / sizeof(table[0]); i++) {
		if (table[i] >= n) {
			printf("%i\n",table[i]);
			break;
		}
  }
  return 0;
}