#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 + 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;
}