n,m,d = list(map(int,input().split()))



if d==0:

    print(((m-1)/n))

else:

    print((2*(n-d)*(m-1)/n**2))
N, M, D = list(map(int, input().split()))

if D == 0:

    print(((M - 1) / N))

else:

    print(((N - D) * (M - 1) * 2 / (N ** 2)))
n, m, d = list(map(int, input().split()))
if d == 0:
    print(((m - 1) / n))
else:
    print((2 * (n - d) * (m - 1) / n**2))

N, M, D = list(map(int, input().split()))
if D == 0:
    print(((M - 1) / N))
else:
    print(((N - D) * (M - 1) * 2 / (N**2)))

-n, m, d = list(map(int, input().split())) -if d == 0: -    print(((m - 1) / n)) +N, M, D = list(map(int, input().split())) +if D == 0: +    print(((M - 1) / N)) -    print((2 * (n - d) * (m - 1) / n**2)) +    print(((N - D) * (M - 1) * 2 / (N**2)))