import core.bitop;
import std.algorithm;
import std.array;
import std.ascii;
import std.container;
import std.conv;
import std.format;
import std.math;
import std.random;
import std.range;
import std.stdio;
import std.string;
import std.typecons;

void main()
{
  string s = readln.chomp;
  int ans = 0;
  foreach (int i, c; s) {
    int sub = 0;
    foreach (int j; 0..cast(int)s.length) {
      int left = i - j;
      if (left < 0) {
        break;
      }
      int right = i + j;
      if (right >= s.length) {
        break;
      }
      // stderr.writeln("\t", s[left], s[right], s[left] == s[right]);
      sub += s[left] == s[right];
    }
    // stderr.writeln(i, " ", sub);
    ans = max(ans, sub * 2 - 1);
    int sub2 = 0;
    foreach (int j; 0..cast(int)s.length) {
      int left = i - j - 1;
      if (left < 0) {
        break;
      }
      int right = i + j;
      if (right >= s.length) {
        break;
      }
      sub2 += s[left] == s[right];
    }
    ans = max(ans, sub2 * 2);
  }
  ans.writeln;
}