#get input
inputs = input()
list = inputs.split()
n = int(list[0])
m = int(list[1])

firstCut = n -1
if (m > 1):
	secCut = m - 1
else:
	secCut = m

#Find max cuts
firstCut 

if(m > 1):
	res = n*m -1
else:
	res = firstCut
print(res)