import sys
from collections import deque

dq = deque()
for (i,c) in enumerate(sys.stdin.read()):
	equals = list(filter(lambda x: c == x[1], enumerate(dq)))
	if len(equals)>0: # remove left part until a char equal to c, included
		for _ in range(equals[-1][0]+1):
			dq.popleft()
	if len(dq) == 13: # if we have 13+1 distinct chars, we're good
		print(i+1)
		break
	dq.append(c)