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