#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include<bits/stdc++.h>
using namespace std;


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