#include <bits/stdc++.h>
using namespace std;

int main() {
    int n, k;
    cin >> n >> k;
    int ans = 0;
    if(n % 2 == 0) ans = min(n / 2, (2 * k + 1) / 2 + 1);
    else ans = min(n, (2 * k + 1) / 2 + 1);

    cout << ans << endl;

    return 0;
}