def main():
    n = input()
    b = 0
    i = 0
    l = n
    while i <= len(n):
        if (l == l[::-1]):
            b = i
        l = n
        i = i + 1
        l = l[0:(i-1)]+l[i:]
    print(b)

if __name__ == '__main__':
    main()