#include<bits/stdc++.h>
using namespace std;
#define mod 1000000007
#define pb push_back
#define mp make_pair
#define Int long long
#define fs first
#define sc second
#define gcd __gcd
#define inf 1e15
int main(){
	
	Int n,m,ans=0;
	cin>>n>>m;
	ans = n-1;
	ans += n*(m-1);
	cout<<ans<<endl;
	return 0;
}