p, q = map(int, input().split())
win = 1 / 3


def dfs(depth, now, P):
    global win
    if depth >= 21:
        return

    # 必勝法使う
    tmp = now * (P/100) * (1/2)
    win += tmp
    Pnext = max(0, P - q)
    dfs(depth + 1, tmp, Pnext)

    # 使わない
    tmp = now * (1 - P/100) * (1/3)
    win += tmp
    Pnext = min(100, P + q)
    dfs(depth + 1, tmp, Pnext)
    return


dfs(0, 1/3, p)
print(win)