题解 | #汽水瓶#

#include <stdio.h>

int main()
{
    int n=0;
    while(scanf("%d\n",&n)!=EOF)
    {
        int able=0;
        if(n==0)
          break;
        while(n>1)
        {
            if(n>=3)
            {
                n-=3;
                able++;
                n++;
            }
            if(n==2)
            {
                able++;
                n=0;
            }
         }
        printf("%d\n",able);
    }
    return 0;
}