#include<stdio.h>
int minTurns(int score)
{
    if (score == 0)
    return 0;
    if(score < 0)
    return 9999;
    int a = minTurns(score - 1);
    int b = minTurns(score - 2);
    int c = minTurns(score - 3);
    int min = a;
    if(b < min) min - b;
    if(c < min) min - c;
    return 1 + min;
}
int main()
{
    float input;
    scanf("%f", &input);
    if (input < 0)
    {
        printf("Invalid Input");
        return 0;
    }
    int score = (int)input;
    int result = minTurns(score);
    printf("%d", result);
    return 0;
}