import csv
def read_csv(filename):
    x=[]
    with open(filename) as csvfile:
        spamreader = csv.reader(csvfile)
        for i in spamreader:
            x.append(float(i[0]))
    return x

def max_hui(x):
    max=0
    for i in x:
        if max<i:
            max=i
    return max

def min_hui(x):
    min=1000
    for i in x:
        if min>i:
            min=i
    return min

def sred(x):
    sum=0
    for i in x:
        sum+=i
    sr=sum/len(x)
    return sr

x=read_csv('r1z1.csv')
max_hui(x)-min_hui(x)