import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines

x,y = map(int,read().split())

ev_x = x%2 == 0
ev_y = y%2 == 0
if ev_x and ev_y:
    answer = (x+1) * (y+1) - max(x,y)
    if x == y:
        answer -= 1
elif ev_x and (not ev_y):
    answer = (x+1) * (y+1) - y
elif (not ev_x) and ev_y:
    answer = (x+1) * (y+1) - x
else:
    answer = (x+1) * (y+1) - min(x,y)

if x == 0:
    answer = 1
if y == 0:
    answer = 1
if x + y == 0:
    answer = 0

print(answer)