/* -*- coding: utf-8 -*-
 *
 * 588.cc: No.588 空白と回文 - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

/* typedef */

/* global variables */

/* subroutines */

/* main */

int main() {
  string s;
  cin >> s;

  int n = s.size();
  int maxl = 0;

  // center == s[i]
  for (int i = 0; i < n; i++) {
    int l = 1;
    for (int j = i - 1, k = i + 1; j >= 0 && k < n; j--, k++)
      if (s[j] == s[k]) l += 2;
    if (maxl < l) maxl = l;
  }

  // center == between s[i] and s[i + 1]
  for (int i = 0; i < n; i++) {
    int l = 0;
    for (int j = i, k = i + 1; j >= 0 && k < n; j--, k++)
      if (s[j] == s[k]) l += 2;
    if (maxl < l) maxl = l;
  }

  printf("%d\n", maxl);
  return 0;
}