#include <algorithm>
#include <cmath>
#include <cstdint>
#include <cstdio>
#include <iomanip>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <vector>
using namespace std;
#define rep(i, n) for(int(i) = 0; (i) < (n); (i)++)
#define FOR(i, m, n) for(int(i) = (m); (i) < (n); (i)++)
#define All(v) (v).begin(), (v).end()
#define pb push_back
#define MP(a, b) make_pair((a), (b))
using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
const int INF = 1 << 30;
const ll LINF = 1LL << 60;
const int MOD = 1e9 + 7;

int main() {
    int N, K;
    cin >> N >> K;
    if(K % 2 == 0) {
        if(N % 2 == 0) {
            cout << min(K + 1, N / 2) << endl;
        } else {
            cout << min(K + 1, N - 1) << endl;
        }
    } else {
        if(N % 2 == 0) {
            cout << min(N / 2, (K / 2 + 1) * 2) << endl;
        } else {

            cout << min(N - 1, (K / 2 + 1) * 2) << endl;
        }
    }
    return 0;
}