#include<stdio.h>
int minTurns(int n)
{
    if (n == 0)
    return 0;
    if (n < 0)
    return 999;
    int a = minTurns(n - 1);
    int b = minTurns(n - 2);
    int c = minTurns(n - 3);
    if(a <= b && b <=c)
    return 1 + a;
    else if (b < =a && b <= c)
    return 1 + b;
    else
    return 1 + c;
}
int main()
{
    int score;
    scanf("%d", &score);
    if (score < 0)
    printf("Invalid Input");
    else
    printf("%d", minTurns(score));
    return 0;
}