#include<bits/stdc++.h>
#define ll long long 
#define pb push_back
#define mp make_pair
#define mod 1000000007
#define fast ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define afor(i,a,b) for(int i=a;i<b;++i)
using namespace std;
 int main()
{
  fast
  ll n,m,i,j,ans=0;
  cin>>n>>m;
  ans+=(n*m)-1;
  cout<<ans<<"\n";
  return 0;
}