#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define srep(i,s,t) for (int i = s; i < t; ++i)
#define drep(i,n) for(int i = (n)-1; i >= 0; --i)
using namespace std;
typedef long long int ll;
typedef pair<int,int> P;
#define yn {puts("YES");}else{puts("NO");}
#define MAX_N 200005

int main() {
    int n, k;
    cin >> n >> k;

    int ans = 0;

    if(n % 2 == 0){
        if(k * 2 >= n){
            cout << n / 2 << endl;
        }else{
            cout << k + 1 << endl;
        }
    }else{
        if(n-1 <= k){
            cout << n << endl;
        }else{
            cout << k + 1 << endl;
        }
    }


    return 0;
}