/*
        SUPTO
        UNIVERSITY OF DHAKA
*/
#include <bits/stdc++.h>
using namespace std;
#define D(x) cerr<<#x " = "<<(x)<<endl
#define pb push_back
#define ff first
#define ss second
#define mem(a) memset(a,0,sizeof(a))
#define _set(a) memset(a,-1,sizeof(a))
typedef long long int ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
#define eps 1e-9
#define MAX 20
#define MAXL 20
#define MAXE 100000
#define inf (1<<29)
//const int mod = 100000007;
//int dx[] = {0,0,1,-1};
//int dy[] = {1,-1,0,0};
//int dx[] = {-1,-1,-1,0,0,1,1,1};
//int dy[] = {-1,0,1,-1,1,-1,0,1};

int main()
{
    //freopen("input.txt", "r", stdin);
    //freopen("output.txt", "w", stdout);
    //ios_base::sync_with_stdio(false);
    ll n, m;
    scanf("%lld %lld", &n, &m);
    printf("%lld\n", n*m-1);
    return 0;
}