/*input
3 3
*/
//__author__= "Rushal Verma"
#include<bits/stdc++.h>
using namespace std;
/*******useful typedef's *********/
typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<vi> vii;
typedef pair<int,int> pii;
typedef list<int>li;
typedef list<li>lii;
typedef set<int>si;
typedef set<ll> sl;
typedef set<si>sii;
typedef map<int,int> mi;
typedef map<ll, ll> mll;
/**************some useful macros/preprocessor********/
#define be_fast std::ios::sync_with_stdio(false);std::cin.tie(NULL); std::cout.tie(NULL);
#define print cout <<
#define ict int t;cin>>t;while(t--)
#define loop(a,b,c)   for (int (a)=(b); (a)<(c); ++(a))
#define loopn(a,b,c)  for (int (a)=(b); (a)<=(c); ++(a))
#define loopd(a,b,c)  for (int (a)=(b); (a)>=(c); --(a))
#define MOD 1000000007
#define INF 0x3f3f3f3f
#define limit 100000+5
#define pb push_back
#define mp make_pair
#define X first
#define Y second
///iterator range
#define all(c) c.begin(), c.end()
///reverse all iterator
#define rall(c) c.rbegin(),c.rend()
#define tr(c,i) for(typeof((c).begin() i = (c).begin(); i != (c).end(); i++))
#define present(c,x) ((c).find(x) != (c).end())
#define cpresent(c,x) (find(all(c),x) != (c).end())
/***************all user defines functions ******************/
/******************main starts here *************************/
int main()
{   be_fast;
	// freopen("source.in", "rt", stdin);
	// freopen("output.out", "wt", stdout);
	ll n, m;
	cin>>n>>m;
	cout<<n*m-1;
return 0;
}
/*******************main ends here **************************/