#include <iostream>
#include <algorithm>
long long NOD(long long a,long long b)
{
	long long t;
	while(b!=0)
	{
		t=b;
		b=a%b;
		a=t;
	}
	return a;
}
using namespace std;
int main ()
{
	long long m,n,gcd;
	cin>>m>>n;
	if(m==n)cout<<1<<endl;
	else
	{
		gcd=NOD(m-1,n-1);
		gcd=gcd*2-1;
		gcd++;
		cout<<(2*m+2*n-2)/gcd-2<<endl;
	}
	return 0;
}
