#include<stdio.h>
int minturns(int n
{
    if(n == 0) return 0;
    if (n < 0) return 100000;
    int a = minturns(n - 1);
    int b = minturns(n - 2);
    int c = minturns(n - 3);
    int min = a;
    if (b < min) min = b;
    if (c < min) min = c;
    return 1 + min;
}
int main() 
{
    int n;
    scanf("%d",&n);
    if (n < 0) {
        printf("Invalid input");
    } else {
        printf("%d",minturns(n));
    }
    return 0;
}