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


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */
    long int n,m;
    cin>>n>>m;
    if(m==1)
    {
        cout<<(n-1);
    }
    else if(n==1)
    {
        cout<<(m-1);
    }
    else
    {
        cout<<((n-1)+((m-1)*n));
    }
    return 0;
}