from functools import lru_cache

P, Q = map(int, input().split())


@lru_cache
def rec(p: int, n: int) -> float:
    if n > 20:
        return 0
    pf = p / 100

    res = 0
    res += pf / 2
    res += pf / 2 * rec(max(p - Q, 0), n + 1)
    res += (1 - pf) / 3
    res += (1 - pf) / 3 * rec(min(p + Q, 100), n + 1)
    return res


ans = 1 / 3 * rec(P, 1) + 1 / 3
print(ans)