#include <cmath>
#include <vector>
#include <iostream>
#include <algorithm>
#include <functional>
using namespace std;
const int inf = 1012345678;
int main() {
	cin.tie(0);
	ios_base::sync_with_stdio(false);
	int N, K;
	cin >> N >> K;
	cout << min(N % 2 == 0 ? N / 2 : N, K + 1) << endl;
	return 0;
}