CodeForces-124A-The number of positions

Petr stands in line of n people, but he doesn't know exactly which position he occupies. He can say that there are
no less than a people standing in front of him and no more than
b people standing behind him. Find the number of different positions Petr can occupy.

Input

The only line contains three integers n,
a and
b (0 ≤ a, b < n ≤ 100).

Output

Print the single number — the number of the sought positions.

Example

Input

3 1 1

Output

2

Input

5 2 3

Output

3

Note

The possible positions in the first sample are: 2 and 3 (if we number the positions starting with 1).

In the second sample they are 3, 4 and 5.

   

    题意：告诉一堆人中你前面最少有几人，后面最多有几人，输出所有可能的位置。

      一道简单的数学题，若a+b<n，则b到n之间的位置都可以。若a+b>=n，则n-a到n都是可以的。

AC代码：

#include <iostream>
#include <stdio.h>
#include <math.h>
#include <string.h>
using namespace std;

int main()
{
int n,a,b;
while(~scanf("%d%d%d",&n,&a,&b))
{
if(a+b>=n)
{
printf("%d\n",n-a);
}
else if(a+b<n)
{
printf("%d\n",b+1);想一下，为什么要加1，不知道的再看一下题目。
}
}
return 0;
}