CF Little Artem andPresents 分糖果的小问题

Little Artem andPresents

Time Limit:2000MS     Memory Limit:262144KB     64bit IO Format:%I64d & %I64u

Submit Status

Description

LittleArtem got n stones on hisbirthday and now wants to give some of them to Masha. He knows that Masha caresmore about the fact of receiving the present, rather than the value of thatpresent, so he wants to give her stones as many times as possible. However,Masha remembers the last present she received, so Artem can't give her the samenumber of stones twice in a row. For example, he can give her3 stones,then 1 stone, then again 3 stones,but he can't give her 3 stonesand then again 3 stones rightafter that.

Howmany times can Artem give presents to Masha?

Input

Theonly line of the input contains a single integer n (1 ≤ n ≤ 10⁹) —number of stones Artem received on his birthday.

Output

Printthe maximum possible number of times Artem can give presents to Masha.

Sample Input

Input

1

Output

1

Input

2

Output

1

Input

3

Output

2

Input

4

Output

3

 

题意：你有 n 个糖果，想要送给自己钟意的人，两次送的个数不能够相同，问有多少种送法。

 

解法：想要玩的时间最长，就 1,2,1,2,1,2,1,2……的送。

/*=============================AC情况===============================*//*题目网址:   *//*时间： *//*心得： 还以为有递推公式，看到 n 的范围。。。。  */#include<stdio.h>#include<stdlib.h>#include<string.h>#define G 100int main() {int n,ans;while(scanf("%d",&n)!=EOF) {ans=2*(n/3);if(n%3!=0) {ans++;}printf("%d\n",ans);}return 0;}/*********************************测试数据***********************************************************************************************************/