#include <bits/stdc++.h>

 using namespace std;

 typedef long long ll;

 const int INF = 0x3f3f3f3f;

 const int M = +;

 int n, m;

 int main()  {

     while( ~scanf("%d %d", &n, &m ) )   {

         if( n ==  )    {

             printf("1\n");

             continue;

         }

         if( m > n/ )

             printf("%d\n", m- );

         else

             printf("%d\n", m+ );

     }

     return ;

 }