import sys
from collections import defaultdict
s = input()
n = len(s)
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
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")