# simupres 
# Fig. 31.3 
# input: 35 5 124

import random

NUM_TRIALS = 32000

n,m,max = map(int, input("n m max=? ").split())
b = [0]*n
count = 0
for k in range(NUM_TRIALS): 
  for i in range(n):
    b[i] = 0
  rs = 0
  for i in range(m): 
    while True:
      r = random.randint(0,n-1)
      if b[r] == 0:
        break
    rs += (r+1)
    b[r] = 1
  if rs >= max:
    count += 1
print(f"count == {count}; P == {count/NUM_TRIALS:.8f}")