#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<(int)(n);i++)
using namespace std;
using ll = long long ;
using P = pair<int,int> ;
using pll = pair<long long,long long>;
constexpr int INF = 1e9;
constexpr long long LINF = 1e17;
constexpr int MOD = 1000000007;

int main(){
    int n,k;
    cin >> n >> k;
    ll ans = 0;
    if(n%2==0){
        if(2*k < n){
            ans = k+1;
        }else{
            ans = n/2;
        }
    }else{
        if(k <= n-1){
            ans = k+1;
        }else{
            ans = n;
        }
    }
    cout << ans << endl;
    return 0;
}