def main():
   
   S = input()
   lenS = len(S)
   
   ans = 0
   for i in range(lenS-1):
   	  for j in range(i, lenS):
   	  	  p = S[i:j+1]
   	  	  if p == p[::-1]:
   	  	  	  if j - i + 1 == lenS:
   	  	  	  	  continue
   	  	  	  ans = max(ans, j - i + 1)
   	  	  	  
   print(ans)
   
if __name__ == '__main__':
    main()