#include<stdio.h>
int minTurns(int n){
    if ( n == 0)
    return 0;
    if (n < 0)
    retrun 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;
        
    }