import std.algorithm, std.conv, std.range, std.stdio, std.string;

void main()
{
  auto s = readln.chomp, n = s.length;

  auto ans = 0;
  foreach (i; 0..n) {
    auto r = 1;
    foreach (j; 1..min(i+1,n-i))
      if (s[i-j] == s[i+j]) r += 2;
    ans = max(ans, r);

    r = 0;
    foreach (j; 0..min(i+1,n-i-1))
      if (s[i-j] == s[i+1+j])
        r += 2;
    ans = max(ans, r);
  }

  writeln(ans);
}