/*********                      Muntasher Morshed                     *********/
/*********                            Submit                          *********/
/*********                  University of Asia Pacific                *********/

#include<bits/stdc++.h>

#define sf scanf
#define sf1(a) scanf("%d",&a)
#define sf2(a,b) scanf("%d %d",&a,&b)
#define pf printf
#define pfC(ca) printf("Case %d: ",ca)
#define li long int
#define lli long long int
#define ll long long
#define loop0(i,n) for(i=0; i<n; i++)
#define loop1(i,n) for(i=1; i<=n; i++)
#define rloop0(i,n) for(i=n-1; i>=0; i--)
#define rloop1(i,n) for(i=n; i>0; i--)
#define maxn 100000
#define pi1 3.1415926535897932385
#define pi2 2*(acos(0.0))
#define pb push_back
#define fill(a,val) memset(a,val,sizeof(a))
using namespace std;
int main()
{
    lli n,m;
    cin>>n>>m;
    cout<<n*m-1<<endl;;
    return 0;
}