#include <stdio.h>
int main() {
int n;
scanf("%d",&n);
int a = n % 8;
int b = a % 6;
int num;
if(a == 0)
{
num = n / 8;
printf("%d\n",num);
return 0;
}
if((a != 0) && (b == 0))
{
num = ((n - a) / 8) +1;
printf("%d\n",num);
return 0;
}
if(a == 4)
{
num = n / 8 + 1;
printf("%d\n",num);
return 0;
}
if(a == 2)
{
num = n / 8 + 1;
printf("%d\n",num);
return 0;
}
printf("-1");
return 0;
}



京公网安备 11010502036488号