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

#define ll long long
ll n,m;
long long ans = 0;

int main() {
    cin>>n>>m;
    ans += (m-1);
    ans += (m*(n-1));
    cout<<ans<<endl;
    return 0;
}