#include<stdio.h>
#include<string.h>
#include<cmath>
#include<iostream>
#include<algorithm>
#include<vector>
#include<queue>
#include<stack>
using namespace std;
int main()
{
    int n,m;
    while(scanf("%d%d",&n,&m)!=EOF)
    {
        m%=n;
        if(m==0)
            printf("%d\n",n-1);
        else printf("%d\n",m-1);
    }
}