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

int n, m;

int main() {
    cin>>n>>m;
    cout<<1LL*(min(n,m)-1) + 1LL*(max(n,m)-1LL)*(min(m,n))<<endl;
    return 0;
}