#include<cstdio>
#include<iostream>
using namespace std;
typedef long long LL;
LL A,B;
class miku
{
public:
	LL x,y;
};
miku gcd(LL x,LL y)
{
	miku tem;
	if(y==0)
	{
		tem.x=1;tem.y=0;
	}
	else
	{
		miku before=gcd(y,x%y);
		tem.x=before.y;
		tem.y=before.x-(x/y)*before.y;
	}
	return tem;
}
int main()
{
	freopen("mod.in","r",stdin);
    freopen("mod.out","w",stdout);
	cin>>A>>B;
	miku ans=gcd(A,B);
	ans.x=(ans.x+B)%B;
	cout<<ans.x;
	return 0;
}