#include <stdio.h>
#include <bits/stdc++.h>
using namespace std;
 

#include <vector>
#include <utility>


#include <algorithm>


int n,m;

void solve() {
	scanf("%d %d", &n, &m);
    if (n > m) swap(n,m);
	printf("%lld\n", n*1ll*m-1);
}


int main() {
    solve();
}