#include <fstream>

using namespace std;
ifstream fin("inversmodular.in");
ofstream fout("inversmodular.out");
void gcd(long long &x,long long &y,int a,int b)
{
    if(b==0)
    {
        x=1;
        y=0;
    }
    else
    {
        long long x0,y0;
        gcd(x0,y0,b,a%b);
        x=y0;
        y=x0-(a/b)*y0;
    }
}
int main()
{
    int n,m;
    long long x=0,y;
    fin>>n>>m;
    gcd(x,y,n,m);
    if(x<=0) x=(n+x)%n;
    fout<<x;
}