#yuki_360
import itertools
import sys

def kado(s):
 l=len(s)
 for i in xrange(l-2):
  if s[i]<s[i+1]>s[i+2] or s[i]>s[i+1]<s[i+2]:
   continue
  else:
   return False
 return True

a=map(int,raw_input().split())
plist=list(itertools.permutations(a))
for i in xrange(len(plist)):
 if kado(plist[i])==True:
  print "YES"
  sys.exit()
print "NO"