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.
#include <iostream> #include <stdio.h> #include <algorithm> using namespace std; int main() { int n,a,b; scanf("%d %d %d",&n,&a,&b); printf("%d ",min(n-a,b+1)); }