#include<stdio.h>

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

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

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