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

#define ll long long int
#define pii pair<int,int>
#define pll pair<ll,ll>
#define vi vector<int>
#define pb push_back
#define mp make_pair
#define fr first
#define se second
#define MOD 1000000007

int main ()
{
	//freopen("input.txt","r",stdin);
	ios_base::sync_with_stdio(false);
    ll n,m;
    cin>>n>>m;
    cout<<n*m-1<<endl;
	return 0;
}