#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 */   
    int n, m;
    cin>>n>>m;
    if(m==1||n==1){
        if(m>n){
            cout<<m-1;
            return 0;       
        }
        else{
            cout<<n-1;
            return 0;
        }
    }
    else{
        cout<<m*n-1;
    }
    return 0;
}