/*
 *  p.cpp
 *  Created on: Aug 23, 2016
 *  Author: Tarun Anand
 *  Copyright (c) 2016 Tarun Anand. All rights reserved.
 */
#include<bits/stdc++.h>
#include<sstream>
using namespace std;
#define mod 1000000007
#define all(v) v.begin(),v.end()
#define loop(i,a,b) for(i=a;i<b;i++)
#define revloop(i,a,b) for(i=a;i>=b;i--)
#define stloop(it,v) for(it=v.begin();it!=v.end();++it)
#define ii pair<int,pair<int,int> >
#define MP make_pair
#define pb push_back
#define ll long long int
#define fill(v,d) memset(v,d,sizeof(v))
int main()
{  std::ios::sync_with_stdio(false);
   cin.tie(0);
   cout.tie(0);
   ll n,m;
   cin>>n>>m;
   cout<<(n*1LL*m)-1;
   return 0;
}