#include<stdio.h>
int minTruns(int n)
{
    if(n== 0)
    return 0;
    if(n < 0)
    return 1000;
    int t1 = minTruns(n - 1);
    int t2 = minTruns(n - 2);
    int t3 = minTruns(n - 3);
    int min =t1;
    if(t2 < min)min = t2;
    if(t3 < min)min = t3;
    return 1+min;
}
int main()
    {
        float f;
        it n;
        scanf("%f",&f);
        n = (int)f;
        if(f < 0)
        printf("Invalid Input\n");
        else
        printf("%d\n",minTruns(n));
        return 0;
    }