#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;
}