#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, a, b;
  cin >> n >> a >> b;
  if (n - a <= b) {
    cout << n - a << endl;
  } else {
    cout << b + 1 << endl;
  }
  return 0;
}

### Prompt

Your challenge is to write a CPP solution to the following problem:

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.

Examples

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.

### Response

```cpp
#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, a, b;
  cin >> n >> a >> b;
  if (n - a <= b) {
    cout << n - a << endl;
  } else {
    cout << b + 1 << endl;
  }
  return 0;
}

```