a, b, _, d = map(int, input().split())

score = 0
cnt = 0

for _ in range(b):
    cnt += 1
    score += 50 * (2**((cnt-1)//100))

for _ in range(a):
    cnt += 1
    score += 100 * (2**((cnt-1)//100))


print([score, 'Impossible'][d >= 10])