# -*- coding: utf-8 -*-

from math import log2



line = list(map(int, input().split(" ")))

n = line[0]

m = line[1]

d = line[2]



if 2*d<n and d>0:

    ret1 = 1+(m-2)*log2(n)

    ret2 = log2(n-d)

    ret3 = log2(m-1)

    ret4 = m*log2(n)

    print((2**(ret1+ret2+ret3-ret4)))

else:

    ret1 = (m-1)*log2(n)

    ret2 = log2(m-1)

    ret3 = m*log2(n)

    print((2**(ret1+ret2-ret3)))

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



if d == 0:

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

else:

    print((2*(n-d)*(m-1)/n/n))
# -*- coding: utf-8 -*-
from math import log2

line = list(map(int, input().split(" ")))
n = line[0]
m = line[1]
d = line[2]
if 2 * d < n and d > 0:
    ret1 = 1 + (m - 2) * log2(n)
    ret2 = log2(n - d)
    ret3 = log2(m - 1)
    ret4 = m * log2(n)
    print((2 ** (ret1 + ret2 + ret3 - ret4)))
else:
    ret1 = (m - 1) * log2(n)
    ret2 = log2(m - 1)
    ret3 = m * log2(n)
    print((2 ** (ret1 + ret2 - ret3)))

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

-# -*- coding: utf-8 -*- -from math import log2 - -line = list(map(int, input().split(" "))) -n = line[0] -m = line[1] -d = line[2] -if 2 * d < n and d > 0: -    ret1 = 1 + (m - 2) * log2(n) -    ret2 = log2(n - d) -    ret3 = log2(m - 1) -    ret4 = m * log2(n) -    print((2 ** (ret1 + ret2 + ret3 - ret4))) +n, m, d = list(map(int, input().split())) +if d == 0: +    print(((m - 1) / n)) -    ret1 = (m - 1) * log2(n) -    ret2 = log2(m - 1) -    ret3 = m * log2(n) -    print((2 ** (ret1 + ret2 - ret3))) +    print((2 * (n - d) * (m - 1) / n / n))