#coding: utf-8
##yuki_21

l=int(raw_input())
n=int(raw_input())
s=[]
while True:
 try:
  a=raw_input()
  if a=='':
   break
  s.append(a)
 except(EOFError):
  break
sn=map(int,s)
sn.sort()

res=sn[-1]-sn[0]

print res