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