#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
ll mod = 1000000007;

ll r(ll x, ll y) {
  if (y == 0) return 1;
  else if (y % 2 == 0) return r(x, y/2) * r(x, y/2) % mod;
  else return x * r(x, (y-1)/2) % mod * r(x, (y-1)/2) % mod;
}

int main() {
  ll n, k;
  cin >> n>> k;
  if (n % 2 == 0) {
    if (k % 2 == 0) {
      k /= 2;
      ll sum = 1;
      sum += (2 * k);
      if (sum > n / 2) {
        sum =  n / 2;
      }
      printf("%lld\n", sum);
    }
    else {
      k = k / 2;
      ll sum = 2;
      sum += (2 * k);
      if (sum  > n / 2) {
        sum = n / 2;
      }
      printf("%lld\n", sum);
    }
  } 

  else {
    if (k % 2 == 0) {
      k /= 2;
      ll sum = 1;
      sum += (2 * k);
      if (sum > n) {
        sum = n;
      }
      printf("%lld\n", sum);
    }
    else {
      k = k / 2;
      ll sum = 2;
        sum += (2 * k);
      if (sum > n) {
        sum = n;
      }
      printf("%lld\n", sum);
    }
  } 
}