def hd(t, j):
    c = 2 * j
    b = c - 1
    g = (b + 1) // 2 + 1
    return t + j + c + b + g


def s(n):
    return 2 * n


def bc(t, j, n):
    return s(n) * 0.5 + hd(t, j) * 0.75