C语言——codeforces979A 题解

A. Pizza, Pizza, Pizza!!!

time limit per test

1 second

memory limit per test

128 megabytes

input

standard input

output

standard output

Katie, Kuro and Shiro are best friends. They have known each other since kindergarten. That's why they often share everything with each other and work together on some very hard problems.

Today is Shiro's birthday. She really loves pizza so she wants to invite her friends to the pizza restaurant near her house to celebrate her birthday, including her best friends Katie and Kuro.

She has ordered a very big round pizza, in order to serve her many friends. Exactly nn of Shiro's friends are here. That's why she has to divide the pizza into n+1n+1 slices (Shiro also needs to eat). She wants the slices to be exactly the same size and shape. If not, some of her friends will get mad and go home early, and the party will be over.

Shiro is now hungry. She wants to cut the pizza with minimum of straight cuts. A cut is a straight segment, it might have ends inside or outside the pizza. But she is too lazy to pick up the calculator.

As usual, she will ask Katie and Kuro for help. But they haven't come yet. Could you help Shiro with this problem?

Input

A single line contains one non-negative integer nn (0≤n≤10180≤n≤1018) — the number of Shiro's friends. The circular pizza has to be sliced into n+1n+1 pieces.

Output

A single integer — the number of straight cuts Shiro needs.

Examples

input

Copy

3

output

Copy

2

input

Copy

4

output

Copy

5

Note

To cut the round pizza into quarters one has to make two cuts through the center with angle 90∘90∘ between them.

To cut the round pizza into five equal parts one has to make five cuts.

思路分析：

n为盆友数量	披萨需要切成n+1块	输出
n是奇数	n+1是偶数	（n+1）/2
n是偶数	n+1是奇数	n+1
n是0		0

注意事项：1. 变量n 要开成long long 的形式（我开始设的int ，oj判题系统过不了）

                   2. n为0这种情况需要特别注意，一定要加上，否则判不过

代码如下：

#include<stdio.h>
int main()
{
        long long n;
        scanf("%lld", &n);
        if(n%2 != 0)
        {
            printf("%lld", (n+1)/2);
        }
        if((n%2 == 0) && n != 0)
        {
            printf("%lld", n+1);
        }
        if(n == 0)
        {
            printf("0");
        }

}