#include<stdio.h>

int main(void){
  int N, i, j, tmp, result = 0;
  scanf("%d", &N);

  for (i = 0; 5 * i <= N; i++){
    for (j = 0; j <= i ; j++){
      tmp = N - 5*i - 2*i;
      if (tmp % 3 == 0 && tmp >= 0) result++;
    }
  }

  printf("%d", result);
  return 0;
}