パナソニック2020 B - Bishop
https://atcoder.jp/contests/panasonic2020/tasks/panasonic2020_b
提出
code: python
import math
h, w = map(int, input().split())
if (w == 1 or h == 1):
print(1)
else:
print(math.ceil(h / 2) * math.ceil(w / 2) + math.floor(h / 2) * math.floor(w / 2))