# Enter your code here. Read input from STDIN. Print output to STDOUT

def splitMatrix(m,n):
  if m is 1 and n is 1: return 0
  if m is 1: return n - 1
  if n is 1: return m - 1
  return m * n

m,n = raw_input().strip().split(' ')
m,n = [int(m),int(n)]
print m * n -1