task2b.py

with open('task2a.txt') as f:
    lines = f.read().splitlines()

x = 0
y = 0
aim = 0
for line in lines:
    tmp = line.split(" ")
    if tmp[0] == 'forward':
        x = x + int(tmp[1])
        y = y + (int(tmp[1]) * aim)
    elif tmp[0] == 'up':
        aim = aim - int(tmp[1])
    elif tmp[0] == 'down':
        aim = aim + int(tmp[1])
print (x*y)