题解 | #汽水瓶#

#include <iostream>
#include <algorithm>
using namespace std;
int juice(int num){
    int n,m;
    int result;
    if(num>=3){
        n=num/3;
        m=num%3;
        result=n+juice(n+m);
    }
    if(num==2){
        result=1;

    }
    if(num==1){
        result=0;
    }
    return result;
}

int main() {
    int num;
    while (cin>>num) {
        if(num==0){
            cout<<endl;
        }
        else{
            cout<<juice(num)<<'\n';
        }
    
    }

}