#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int main(){
    long long N, K;
    cin >> N >> K;
    if(N % 2 == 0){
        if(N > K * 2){
            cout << (K * 2 + 1) / 2 + 1 << endl;
            return 0;
        }
        else{
            cout << N / 2 << endl;
            return 0;
        }
    }
    else{
        if(N > K){
            cout << (K * 2 + 1) / 2 + 1 << endl;
            return 0;
        }
        else{
            cout << N << endl;
        }
    }
}