def solve(io)
  s1 = io.get(String)
  s2 = s1.reverse
  n = s1.size

  base = Random.rand((1 << 10)..(1 << 30))
  rh1 = RollingHash.new_string(s1, base)
  rh2 = RollingHash.new_string(s2, base)

  m = 1
  (0...n).each do |i1|
    i2 = n - i1 - 1
    mt = Math.min(i1, i2)
    t = (0...mt).bsearch { |x| rh1[i1, x+1] != rh2[i2, x+1] } || mt

    max_u(m, t * 2)

    l1 = i1 - t - 2
    l2 = n - l1 - 1
    r1 = i1 + t + 1
    r2 = n - r1 - 1
    mu = Math.min(l1, r2)
    if mu > 0
      u = (0...mu).bsearch { |x| rh1[r1, x+1] != rh2[l2, x+1] } || mu
      max_u(m, t * 2 + u * 2 + 1)
    end

    l1 = i1 - t - 1
    l2 = n - l1 - 1
    r1 = i1 + t + 2
    r2 = n - r1 - 1
    mu = Math.min(l1, r2)
    if mu > 0
      u = (0...mu).bsearch { |x| rh1[r1, x+1] != rh2[l2, x+1] } || mu
      max_u(m, t * 2 + u * 2 + 1)
    end

    if i1 < n - 1 && s1[i1] == s1[i1+1]
      j1 = i1 + 1
      j2 = n - j1 - 1
      mt = Math.min(i1, j2)
      t = (0...mt).bsearch { |x| rh1[j1, x+1] != rh2[i2, x+1] } || mt

      max_u(m, t * 2)

      l1 = i1 - t - 2
      l2 = n - i1 - 1
      r1 = i2 + t + 1
      r2 = n - r1 - 1
      mu = Math.min(l1, l2)
      if mu > 0
        u = (0...mu).bsearch { |x| rh1[r1, x+1] != rh2[l2, x+1] } || mu
        max_u(m, t * 2 + u * 2 + 1)
      end

      l1 = i1 - t - 1
      l2 - n - l1 - 1
      r1 = i2 + t + 2
      r2 = n - r1 - 1
      mu = Math.min(l1, l2)
      if mu > 0
        u = (0...mu).bsearch { |x| rh1[r1, x+1] != rh2[l2, x+1] } || mu
        max_u(m, t * 2 + u * 2 + 1)
      end
    end
  end

  io.put m
end

struct Int
  def cdiv(b : Int)
    (self + b - 1) // b
  end

  def bit?(i : Int)
    bit(i) == 1
  end

  def set_bit(i : Int)
    self | (self.class.new(1) << i)
  end

  def reset_bit(i : Int)
    self & ~(self.class.new(1) << i)
  end

  {% if compare_versions(env("CRYSTAL_VERSION") || "0.0.0", "0.34.0") < 0 %}
    def bit_length : Int32
      x = self < 0 ? ~self : self

      if x.is_a?(Int::Primitive)
        Int32.new(sizeof(self) * 8 - x.leading_zeros_count)
      else
        to_s(2).size
      end
    end
  {% end %}
end

struct Int32
  SQRT_MAX = 46_340_i32

  def isqrt
    m = SQRT_MAX
    r = (1_i32..SQRT_MAX).bsearch { |i| i**2 > self }
    r.nil? ? SQRT_MAX : r - 1
  end
end

struct Int64
  SQRT_MAX = 3_037_000_499_i64

  def isqrt
    r = (1_i64..SQRT_MAX).bsearch { |i| i**2 > self }
    r.nil? ? SQRT_MAX : r - 1
  end
end

struct Float64
  def near_zero?
    self.abs < EPSILON
  end
end

struct Number
  {% if compare_versions(env("CRYSTAL_VERSION") || "0.0.0", "1.1.0") < 0 %}
    def zero?
      self == 0
    end

    def positive?
      self > 0
    end

    def negative?
      self < 0
    end
  {% end %}

  {% if compare_versions(env("CRYSTAL_VERSION") || "0.0.0", "0.36.0") < 0 %}
    def self.additive_identity
      zero
    end

    def self.multiplicative_identity
      new(1)
    end
  {% end %}
end

class Array
  macro new_md(*args, &block)
    {% if !block %}
      {% for arg, i in args[0...-2] %}
        Array.new({{arg}}) {
      {% end %}
      Array.new({{args[-2]}}, {{args[-1]}})
      {% for arg in args[0...-2] %}
        }
      {% end %}
    {% else %}
      {% for arg, i in args %}
        Array.new({{arg}}) { |_i{{i}}|
      {% end %}
      {% for block_arg, i in block.args %}
        {{block_arg}} = _i{{i}}
      {% end %}
      {{block.body}}
      {% for arg in args %}
        }
      {% end %}
    {% end %}
  end
end

class ProconIO
  def initialize(@ins : IO = STDIN, @outs : IO = STDOUT)
    @buf = [] of String
    @index = 0
  end

  def get(k : T.class = Int32) forall T
    get_v(k)
  end

  macro define_get
    {% for i in (2..9) %}
      def get(
            {% for j in (1..i) %}
              k{{j}}{% if j < i %},{% end %}
            {% end %}
          )
        {
          {% for j in (1..i) %}
            get(k{{j}}){% if j < i %},{% end %}
          {% end %}
        }
      end
    {% end %}
  end
  define_get

  macro define_getn
    {% for i in (2..9) %}
      def get{{i}}(k : T.class = Int32) forall T
        get(
          {% for j in (1..i) %}
            k{% if j < i %}, {% end %}
          {% end %}
        )
      end
    {% end %}
  end
  define_getn

  def get_a(n : Int, k : T.class = Int32) forall T
    Array.new(n) { get_v(k) }
  end

  def get_c(n : Int, k : T.class = Int32) forall T
    get_a(n, k)
  end

  macro define_get_c
    {% for i in (2..9) %}
      def get_c(
            n : Int,
            {% for j in (1..i) %}
              k{{j}}{% if j < i %},{% end %}
            {% end %}
          )
        a = Array.new(n) do
          get(
            {% for j in (1..i) %}
              k{{j}}{% if j < i %},{% end %}
            {% end %}
          )
        end
        {
          {% for j in (1..i) %}
            a.map { |e| e[{{j-1}}] }{% if j < i %},{% end %}
          {% end %}
        }
      end
    {% end %}
  end
  define_get_c

  macro define_getn_c
    {% for i in (2..9) %}
      def get{{i}}_c(n : Int, k : T.class = Int32) forall T
        get_c(
          n,
          {% for j in (1..i) %}
            k{% if j < i %}, {% end %}
          {% end %}
        )
      end
    {% end %}
  end
  define_getn_c

  def get_m(r : Int, c : Int, k : T.class = Int32) forall T
    Array.new(r) { get_a(c, k) }
  end

  def put(*vs)
    vs.each.with_index do |v, i|
      put_v(v)
      @outs.print i < vs.size - 1 ? " " : "\n"
    end
  end

  def put_e(*vs)
    put(*vs)
    exit
  end

  def put_f(*vs)
    put(*vs)
    @outs.flush
  end


  private def get_v(k : Int32.class); get_token.to_i32; end
  private def get_v(k : Int64.class); get_token.to_i64; end
  private def get_v(k : UInt32.class); get_token.to_u32; end
  private def get_v(k : UInt64.class); get_token.to_u64; end
  private def get_v(k : Float64.class); get_token.to_f64; end
  private def get_v(k : String.class); get_token; end

  private def get_token
    if @buf.size == @index
      str = @ins.read_line
      @buf = str.split
      @index = 0
    end
    v = @buf[@index]
    @index += 1
    v
  end

  private def put_v(vs : Enumerable)
    vs.each_with_index do |v, i|
      @outs.print v
      @outs.print " " if i < vs.size - 1
    end
  end

  private def put_v(v)
    @outs.print v
  end
end

macro min_u(a, b)
  {{a}} = Math.min({{a}}, {{b}})
end

macro max_u(a, b)
  {{a}} = Math.max({{a}}, {{b}})
end

macro zip(a, *b, &block)
  {{a}}.zip({{*b}}) {{block}}
end

class CumulativeSum(T)
  def initialize(a : Array(T))
    @n = a.size
    @s = Array.new(@n+1, T.additive_identity)
    @n.times.each do |i|
      @s[i+1] = @s[i] + a[i]
    end
  end

  getter n : Int32

  def [](start : Int, count : Int)
    @s[start + count] - @s[start]
  end

  def [](r : Range)
    sc = Indexable.range_to_index_and_count(r, @n)
    raise ArgumentError.new("Invalid range") if sc.nil?
    self[*sc]
  end


  @s : Array(T)
end

def powr(a : T, n : Int, i : T = T.multiplicative_identity) forall T
  powr(a, n, i) { |a, b| a * b }
end

def powr(a : T, n : Int, i : T = T.multiplicative_identity, &block) forall T
  return i if n == 0
  r, b = i, a
  while n > 0
    r = yield r, b if n.bit(0) == 1
    b = yield b, b
    n >>= 1
  end
  r
end

def ext_gcd(a : T, b : T) forall T
  if a == 0
    {b, T.new(0), T.new(1)}
  else
    g, x, y = ext_gcd(b%a, a)
    {g, y-(b//a)*x, x}
  end
end

abstract struct ModInt < Number
  macro new_type(name, mod)
    struct {{name}} < ModInt
      @@mod : Int32 = {{mod}}
    end
  end

  def initialize(v : Int)
    @v = (v % @@mod).to_i64
  end

  def_hash @@mod, @v

  def to_s
    @v.to_s
  end

  def to_s(io : IO) : Nil
    @v.to_s(io)
  end

  getter v : Int64

  delegate to_i, to: @v

  def ==(r : self)
    @v == r.v
  end

  def ==(r : Int)
    @v == (r % @@mod)
  end

  def - : self
    m(-@v)
  end

  def +(r : self)
    m(@v + r.v)
  end

  def +(r : Int)
    self + m(r)
  end

  def -(r : self)
    m(@v - r.v)
  end

  def -(r : Int)
    self - m(r)
  end

  def *(r : self)
    m(@v * r.v)
  end

  def *(r : Int)
    self * m(r)
  end

  def //(r : self)
    self * r.inv
  end

  def //(r : Int)
    self // m(r)
  end

  def **(n : Int)
    powr(self, n)
  end

  def inv
    m(ext_gcd(@v.to_i32, @@mod)[1])
  end


  private def m(v : Int)
    self.class.new(v)
  end
end

class RollingHash(T)
  ModInt.new_type(Mint1, 1_000_000_007)
  ModInt.new_type(Mint2,   998_244_353)

  def initialize(a : Array(T), base = random_base)
    @n = a.size

    be1 = Array.new(@n, Mint1.zero); be1[0] = Mint1.new(1)
    be2 = Array.new(@n, Mint2.zero); be2[0] = Mint2.new(1)

    (1...@n).each do |i|
      be1[i] = be1[i-1] * base
      be2[i] = be2[i-1] * base
    end

    @bi1 = Array.new(@n, Mint1.zero); @bi1[-1] = be1[-1].inv
    @bi2 = Array.new(@n, Mint2.zero); @bi2[-1] = be2[-1].inv

    (1...@n).reverse_each do |i|
      @bi1[i-1] = @bi1[i] * base
      @bi2[i-1] = @bi2[i] * base
    end

    @hc1 = CumulativeSum(Mint1).new(a.map_with_index { |e, i| be1[i] * e })
    @hc2 = CumulativeSum(Mint2).new(a.map_with_index { |e, i| be2[i] * e })
  end

  def self.new_string(s : String, base = random_base)
    self.new(s.chars.map(&.ord), base)
  end

  def self.random_base
    Random.rand((1 << 10)...(1 << 30))
  end

  def [](start, count)
    {@hc1[start, count] * @bi1[start], @hc2[start, count] * @bi2[start]}
  end

  def [](r : Range)
    sc = Indexable.range_to_index_and_count(r, @n)
    raise ArgumentError.new("Invalid range") if sc.nil?
    self[*sc]
  end


  @n : Int32
  @bi1 : Array(Mint1)
  @bi2 : Array(Mint2)
end

solve(ProconIO.new)