#include<stdio.h>
int solve(int n)
{
    if (n <= 0)
    return (n == 0) ? 0:
    999999;
    int a = solve(n-1);
    int b = solve(n-2);
    int c = solve(n-3);
    int m = a < b ? a : b;
    if (c < m) m = c;
    return 1 + m;
}
int main()
{
    float X;
    scanf("%f", &X);
    if(X < 0)
    {
        printf("Invalid input");
        return 0;
    }
    int n = (int)x;
    printf("%d", solve(n));
    return 0;
}