from random import *

def X():
    a=random()
    x=1
	if a<=0.25:
		x=0
	if a>=0.75:
		x=2
    return x

def Moyenne(n):
    som=0
    for i in range(n):
        som=som+X()
    m=som/n
    return m

def Ecart(n):
    d=abs(Moyenne(n)-1)
    return d