s,c,i,e,v=input(),6,1,1,0
for c in range(2,len(s)*2-2):
  i,k=1,'' if e else s[c//2]
  while 0<=(c//2-i) and (c//2+i)<len(s):
    a,b=s[c//2-i],s[c//2-e+i]
    if a!=b:a=b=' '
    k=a+k+b
    v=max(v,len(k)-k.count(' '))
    i+=1
  e^=1
print(v)