#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pii;
typedef pair<ll, ll> pll;
typedef vector<ll> vii;
typedef vector<ll> vll;

#define X first
#define Y second
#define rep(i,n) for(ll i=0; i<(n); i++)
#define repp(i,ed,b) for(ll i=ed; i<=(b); i++)
#define repp2(i,b,ed) for(ll i=b; i>=(ed); i--)
#define fill(ed,val) memset(ed, (val), sizeof(ed))
#define mp make_pair
#define pb push_back
#define sz(x) (ll)x.size()
#define all(c) (c).begin(), (c).end()
#define uni(c) c.resize(distance(c.begin(), unique(all(c))))
#define io ios_base::sync_with_stdio(false);cin.tie(NULL);
#define sc(n) scanf("%lld",&n)

#define gc getchar
#define pc putchar
 
inline void get (ll *p){register ll n=0,sign=1,a=gc();while(a<'0'||a>'9'){ if(a=='-'){sign=-1;a=gc();break;} a=gc();}while(a>='0' && a<='9'){n=(n<<1)+(n<<3)+a-'0';a=gc();}*p=n*sign;}

ll mod= 1e9 + 7, mod1=1e9+9;
const ll N=20005,MAX=2e9+5;

int main() {
	
	io;

    ll n,m;
    cin>>n>>m;
    if(n>m)swap(m,n);
    cout<<n*m-1;
	
	
	return 0;
}