记录瓶盖就完事了
水
import java.util.*;
class Main{
public static void main(String[] args) {
Scanner in =new Scanner(System.in);
int n=in.nextInt();
int ans=n;
int p=n;
while(p>2) {
int t=p/3;
ans+=t;
p=p%3+t;

    }
    System.out.println(ans);
}

}