#include<iostream>
#include<cstdio>
#include<cmath>
using namespace std;
#define int long long
int n,d,x,ans;
bool vis[2000001];
signed main(){
	cin>>n>>d;
	ans=0;
	vis[x=1]=true;
	while(1){
		x=(x+d)%n;
		x=x?x:n;
		if(vis[x])break;
		ans++,vis[x]=true;
	}
	cout<<ans;
}