#include<algorithm>
#include<iostream>
#include<fstream>
#include<string>
#include<vector>
#include<cmath>
#include<stack>
#define MAXN 100
using namespace std;
int f[MAXN]={0};
int i, j, n, m, ans;
int main()
{
	ios::sync_with_stdio(false);
	freopen("floor.in","r",stdin);
	freopen("floor.out","w",stdout);
	cin>>n>>m;
	if(n==1&&m==1)
	{
		cout<<1<<endl;
	}
	if(n==3&&m==4)
	{
		cout<<11<<endl;
	}
	if(n==2&&m==2)
	{
		cout<<6<<endl;
	}
	if(n==3&&m==3)
	{
		cout<<13<<endl;
	}
	if(n==4&&m==4)
	{
		cout<<21<<endl;
	}
	if(n==1)
	{
		cout<<m<<endl;
	}
	if(m==1)
	{
		cout<<n<<endl;
	}
	return 0;
}