#include <bits/stdc++.h>
#include<string.h>
#define MAX 1000005
#define MOD 1000000007
#define MA 1200000
#define PI 3.14159265358979323846264338327950
//const int  MAXA=1e15+1;
typedef long long int  ll;
const int INF=1e18;
using namespace std;
const int maxn=1e5+5;
const int ma=1e9+5;
int main()
{
    //freopen("input.txt","r+",stdin);
    //freopen("output.txt","w+",stdout);
    ios::sync_with_stdio(0);
    cin.tie(0);
    ll n,m;
    cin>>n>>m;
    printf("%lld",n*1LL*m-1);
    return 0;
}