#include <fstream>

using namespace std;
ifstream f("inversmodular.in");
ofstream g("inversmodular.out");
int w;
int cmmdc(int a,int b)
{
    while(b)
    {
        w=a%b;
        a=b;
        b=w;
    }
    return a;
}
void euclid(int a,int b,int &x,int &y)
{
    if(b==0)
    {
        x=1;
        y=0;
    }
    else
    {
        int x0,y0;
        euclid(b,a%b,x0,y0);
        x=y0;
        y=x0-(a/b)*y0;
    }
}
int main()
{
    int t,a,b,c,d,e,x,y;
    f>>a>>b;
    euclid(a,b,x,y);
    while(x<0)
        x+=b;
    g<<x;
    return 0;
}