# Hash using polynomials over P mod M
P, M = 31, 1000000009

def to_int(c):
	return ord(c) - ord('0')

S = input()

# We maintain a hash of characters on the left and right
lh, rh, re = 0, 0, 1

# Scan inward from both sides and discard prefix-suffix pairs
# with equal hashes
l, r, ans = 0, len(S)-1, 0

while l < r:
	lh = (lh * P + to_int(S[l])) % M
	rh = (rh + re * to_int(S[r])) % M
	re = re * P % M
	l, r = l+1, r-1

	if lh == rh:
		ans += 2
		lh, rh, re = 0, 0, 1

if l == r or lh != 0 or rh != 0:
	ans += 1

print(ans)