#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() 
{
    long long n,m;
    cin>>n>>m;
    long long sum = 0;
    if(n == 1 || m == 1)
    {
        if(n == 1)
            sum = m-1;
        else
            sum = n-1;
    }
    
    else
    {
        if(n > m)
        {
            long temp = n;
            n = m;
            m = temp;
        }
        sum = m-1;
        sum += (n-1)*m;
    }
    cout<<sum;
    
    return 0;
}