#include<bits/stdc++.h>
using namespace std;
double PI = 3.1415926535897932384626433832795;
#define MOD	1000000007

int main() {
	//freopen("albert.in", "r", stdin);
	//freopen("problems","w",stdout);
	long long n , m;
	cin >> n >> m;
	cout << n*m-1;

	return 0;
}