#include <bits/stdc++.h>

using namespace std;

#define pb push_back
#define mp make_pair

typedef long long int ll;
typedef vector< pair<int,int> > vii;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<long long int> vll;
typedef pair<int,int> pii;

const int INF=INT_MAX;
const int MOD= 1e9+7;

int main()
{
    std::ios::sync_with_stdio(0);

    ll n,m;
    cin>>n>>m;

    cout<<n*m-1<<endl;

    return 0;
}