A. The number of positions

time limit per test
0.5 second

memory limit per test
256 megabytes

input
standard input

output
standard output

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 thana 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.

Sample test(s)

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.

解题说明：这道题就是考虑前a个不能站人，同时要考虑后面的人不能超过b个，分情况判断即可，当总人数过多或a太小时，以b为准，否则就以a为准

#include <iostream>
#include<cstdio>
#include<cstring>
#include<cmath>
using namespace std;

int main()
{
int n,a,b;
int temp1;
int answer;
scanf("%d %d %d",&n,&a,&b);
temp1=n-a;
if(temp1-1>b)
{
answer=b+1;
}
else
{
answer=temp1;
}
printf("%d\n",answer);

return 0;
}