#include<bits/stdc++.h>
#define up(j,k,i) for(i=j;i<k;i++)
#define down(j,k,i) for(i=j;i>k;i--)
#define pp(n) printf("%lld\n",n)
#define is(n) scanf("%lld",&n)
#define ips(n) scanf("%lld",n)
#define ss(s) scanf("%s",s)
#define cool 0
#define pb push_back
#define mp make_pair
#define F first
#define S second
#define f(i) cout<<i<<endl;
#define pll pair<lld,lld> 
#define pi acos(-1)
#define ds(n,m) scanf("%lld %lld",&n,&m)
#define ts(n,m,k) scanf("%lld %lld %lld",&n,&m,&k)
typedef long double ld;
typedef long long int lld;
using namespace std;
const lld M =1e18+7;
const lld mod=1e9+7;
const lld infi =1e18+7;
int main()
{
  lld n,m;
  ds(n,m);
  cout<<(n*m)-1<<endl;
        
        return 0;
}