题解 | #汽水瓶#

#include <iostream>
#include <bits/stdc++.h>
using namespace std;

int main() {
    int initNum;
    int result = 0;
    while(cin >> initNum){
        int result = 0;
        int emptyBottol = initNum;
        while(emptyBottol >= 3)
        {
            result += emptyBottol/3;
            emptyBottol = emptyBottol%3 + emptyBottol/3;
        }
	  // 只有剩余两瓶才有机会靠借多喝一瓶
        if(emptyBottol == 2)result++;
        if(initNum != 0)cout<< result << endl;
    }

}
// 64 位输出请用 printf("%lld")