#include <bits/stdc++.h>
using namespace std;
using ll=long long;
using Graph=vector<vector<pair<int,int>>>;
#define INF 1000000000000000000
#define MOD 1000000007

int main(){
  ll N,K;
  cin>>N>>K;

  if(N%2==0){
    if(K<N/2){
      cout<<K+1<<endl;
    }else{
      cout<<N/2<<endl;
    }
  }else{
    if(K<N){
      cout<<K+1<<endl;
    }else{
      cout<<N<<endl;
    }
  }
}