#include <iostream>

using namespace std;
int main(){
    int n,k; cin >> n >> k;
    if(k + 1<n - k + 1){
        cout << k + 1 << endl;
    }else{
        if(n%2==0){
            cout << min(n/2,k + 1) << endl;
        }else{
            cout << min(n,k + 1) << endl;
        }
    }
}