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(((1*n-2*d)*(m-1)/n**2))

elif n>=2*d:

    print(((2*n-2*d)*(m-1)/n**2))

else:

    print((2*d*(m-1)/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(((1 * n - 2 * d) * (m - 1) / n**2))
elif n >= 2 * d:
    print(((2 * n - 2 * d) * (m - 1) / n**2))
else:
    print((2 * d * (m - 1) / n**2))

-    print(((m - 1) / n)) +    print(((1 * n - 2 * d) * (m - 1) / n**2)) +elif n >= 2 * d: +    print(((2 * n - 2 * d) * (m - 1) / n**2)) -    print((2 * (n - d) * (m - 1) / n**2)) +    print((2 * d * (m - 1) / n**2))