//invers modular O(log n) folosind algoritmul lui euclid extins
#include <fstream>
#include <cstdio>
using namespace std;
ifstream f("inversmodular.in");
ofstream g("inversmodular.out");



int euclid(int a, int b ,int *x , int *y)
{
    if (b==0) {
        *x=1;
        *y=0;
        return a;
    }
    int x0,y0;
    int d=euclid(b,a%b,&x0,&y0);
    *x=y0;
    *y=x0 - (a/b) * y0;
    return d;

}


int main()
{
    int x,y,a,b;
    f>>a>>b;
    int d=euclid(a,b,&x,&y);
    while (x<0)
        x+=b;
    g<<x;

    return 0;
}