import collections
import sys
count = collections.Counter
tgts = []
for _ in range(int(raw_input())):
  i = raw_input()
  tgts.append(swap[i]) 
#print count(tgts)
noise = sorted(count(tgts).values()).pop()
ents =  sum(count(tgts).values()) - noise
if noise >= ents + 2: 
  print "NO"
  sys.exit(0)
print "YES"