import sys
from collections import defaultdict
try:
	s = input()
	n = len(s)
except ValueError:
	print("NO")
	sys.exit()
if n < 2:
	print("NO")
	sys.exit()
d = defaultdict(list)
for i in range(n):
	if s[i] != " ":
		d[s[i]].append(i)
ok = False
if len(d) == 0:
	print("NO")
	sys.exit()
for v in d.values():
	l = len(v)
	tmp = True
	for i in range(l-1):
		if v[i+1] - v[i] != 2:
			tmp = False
	if tmp:
		ok = True
if ok:
	print("Yes")
else:
	print("NO")