题解 | 买橘子

target = int(input())
if(target==6 or target==8):
    print('1')
else:
    buy_number=[]
    count=0
    while target>5:
        if((target-6)%8==0):
            target=target-6
            count+=1
            buy_number.append(int(target/8+count))                     
        else:
            target=target-6
            count+=1           
    if(len(buy_number)==0):
        print('-1')
    else:
        buy_number.reverse()
        print(buy_number[len(buy_number)-1])