#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i=0; i<(n); i++)
using ll = long long;
using P = pair<int,int>;
ll ans;
int main()
{
    ll n,k;cin >>n >> k;
    if(k%2 ){
        ans = 1+k;
    }
    else ans = k+1;
    if(n%2)ans = min(ans,n);
    else ans = min(ans,n/2);
    

    cout<< ans;
    return 0;
}