#include <iostream>
#include <fstream>
#include <vector>
using namespace std;
ifstream fin ("inversmodular.in");
ofstream fout ("inversmodular.out");
int n,a,b,c,d;
int euclid(int a, int b, int &x, int &y)
{
    if (b == 0) {
        x = 1;
        y = 0;
        return a;
    } else {
        int x0, y0;
        int d = euclid(b, a % b, x0, y0);
        x = y0;
        y = x0 - (a / b) * y0;
        return d;
    }
}
int main()
{
    fin >> a>> b ;
    int x=0,y=0;
    d=euclid(a,b,x,y);
    while(x<0)
        x+=b;
    fout  << x;
    return 0;
}