#include<cstdio>
long long a,n;
void euclid(long long a,long long b,long long &x,long long &y,long long &d)
{
	if(b==0)
	{x=1; y=0; d=a; return;}
	long long x1,y1;
	euclid(b,a%b,x1,y1,d);
	x=y1; y=x1-(a/b)*y1;
}
int main()
{
	freopen("inversmodular.in","r",stdin);
	freopen("inversmodular.out","w",stdout);
	scanf("%lld%lld",&a,&n);
	long long x,y,d;
	euclid(a,n,x,y,d);
	if(x<0)
		printf("%lld",n-x%n);
	else
		printf("%lld",x%n);
	return 0;
}