#include<stdio.h>
#include<stdlib.h>
int BottleNum(int n){
int num = 0;
while (n >= 2){
num = num + n / 2;
n = n / 2 + n % 2;
}
return num;
}
int main(){
int n = 0;
int num = 20 + BottleNum(20);
printf("%d\n", num);
system("pause");
return 0;
}