二项系数和时间拥塞概率Python

def binomialco(p,k):
  Sum = 1
  Pro = 1
  for i in range(0,k):
    Sum = Sum*(p-i)
  for i in range(1,k+1):
    Pro = Pro*i
  return float(Sum/Pro)

def P0(s,n,v,h):
  athroisma = 0
  for i in range(0,s+1):
    dent= binomialco(n-1,i)*(v*h)**i
    athroisma+=dent
  return athroisma

s=input()
n=input()
v=input()
h=input()

print P0(s,n,v,h)
def binomialco(p,k):
  Sum = 1
  Pro = 1
  for