题解 | 买橘子

#include <stdio.h>

int main() {
    int n;
    scanf("%d",&n);
    if(n%2==1){
        printf("-1");
        return 0;
    }
    int cnt=n/8,sum=cnt*8;
    int need=n-sum;
    if(need==0)printf("%d",cnt);
    else if((6-need)/2<=cnt){
        printf("%d",cnt+1);
    }
    else printf("-1");
    return 0;
    return 0;
}