#include <map>
#include <set>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <string>
#include <bitset>
#include <cstdio>
#include <limits>
#include <vector>
#include <climits>
#include <cstring>
#include <cstdlib>
#include <fstream>
#include <numeric>
#include <sstream>
#include <iostream>
#include <algorithm>
#include <unordered_map>

using namespace std;

int main ()
{ int n,m ;
  cin >> n>>m ; // n row , m column
  long result ;
  if (n<1 || m <1 ) return 0;
  if (n>1000000000 || m>1000000000 ) return 0;

  long count1= 0;
  long count2=0;

  if (m > 1)
  {   for (int j=1 ; j<m ; j++)
	   count1++ ;
  }

 if (n >1)
  {   for (int i=1 ; i<n ; i++)
      count2++ ;
  }

 count2= count2 * m ;
 result =  count2 + count1 ;
  cout <<  result <<endl;


	return 0;

}