strs = input() ans,res,start ,temp= 0,0,0,[] for i in strs: if i not in temp: temp.append(i) res = len(temp) else: start = temp.index(i) temp = temp[start:] ans = max(ans, res) print(ans)
import sys
try:
while True:
t = input()
l = len(t)
c = 0
for i in range(l):
for j in range(l-i):
lm = len(t[i:l-j])
A = list(set(t[i:l-j]))
ln = len(A)
if lm == ln and lm >= c:
c = lm
break
print(c)
except:
pass