Code War Choco Break Challenge

/* Code Wars asks you to break a chocolate bar with the dimensions into 1X1 pieces. They show you the test cases they will run. 
I realized the algorithm for this would be (n*m -1) based on the examples they gave.
*/

var breakChocolate = function(n, m) {
if (n > 0 && m > 0) {
  return n * m -1
}
else {
  return 0
}
}
//Test Cases Below. Only ran this in their browser.
Test.assertEquals(breakChocolate(5, 5) , 24)
Test.assertEquals(breakChocolate(1, 1) , 0)