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