#include<bits/stdc++.h>
using namespace std;

typedef long int li;
typedef long long ll;
#define mp make_pair
#define pb push_back
#define mid (l+ r>> 1)
#define getc getchar
const li mod= 1e9+ 7;



void solve()
{
	li n, m;

	scanf( "%ld %ld", &n, &m);

	printf( "%lld", 0ll+ n- 1+ n* (m- 1));

	return;
}

int main()
{
	li T= 1;

//	scanf( "%ld", &T);

	while( T--)
	{
		solve();
	}

	return 0;
}