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