#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
int main() 
{   
    long long n,m;
    cin>>n>>m;
    long long ans=0;
    if(n==1 && m==1)
        ans=0;
    else if(n == 1)
        ans=m-1;
    else if(m == 1)
        ans=n-1;
    else if(n >= m)
        ans=(n-1) + n * (m-1);
    else
        ans=(m-1) + m * (n-1);
    cout<<ans;
    return 0;
}