// editor1
#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;
    int n;
    scanf("%f",&f);
    n=(int)f;
    if(f<0)
    printf("Invalid Input\n");
    else
    printf("%d\n", minTruns(n)):
    return 0;
}