C

#2839

#include <stdio.h>

int main(){

    int N;
    int x, y;
    int min = 1000;
    int correct = 0;

    scanf("%d", &N);

    if(N < 3 || N > 5000){
        printf("-1");
    }
    else if(N % 5 == 0 && N % 3 == 0){
        printf("%d", N/5);
    }
    else if(N % 5 == 0 && N % 3 != 0){
        printf("%d", N/5);
    }
    else{

        x = N/5;
        y = N/3;

        for(int i = 0; i <= x; i++){
            for(int j = 0; j <= y; j++){
                if(N == 5 * i + 3 * j){

                    correct = 1;

                    if(min >= i + j){
                        min = i + j;

                    }
                }
            }
        }

        if(correct == 1)
            printf("%d", min);
        else
            printf("-1");
        
    }

    return 0;
}