#include<stdio.h>
#include<math.h>

ingt minSteps(int n) {
    if (n == 0) return 0;
    
    if (n < 0) return 1000;
    
    int step1 = minSteps(n - 1);
    int step2 = minsteps(n - 2);
    int step3 = minSteps(n - 3);
    
    int min = step1;
    if (step2 < min) min = step2;
    if (step3 < min) min = step3;
    
    return 1 + min;
}

int main() {
    float score;
    scanf("%f", &score);
    
    int n = (int)score;
    
    if (score < 0) {
        printf("Invalid Input\n");
    } else {
        printf("%d\n", minSteps(n));
    }
    
    return 0;
}