#include <bits/stdc++.h>

using namespace std;

#define REP(i,n) for(int i=0; i<(int)(n); i++)
#define FOR(i,b,e) for (int i=(int)(b); i<(int)(e); i++)
#define ALL(x) (x).begin(), (x).end()

const double PI = acos(-1);

int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);

  string s;
  cin >> s;

  int ret = 0;

  // one-center
  REP (i, s.length()) {
    int l = i-1;
    int r = i+1;

    int tmp = 1;
    while (l >= 0 && r < s.length()) {
      if (s[l] == s[r])
        tmp += 2;
      --l, ++r;
    }
    ret = max(ret, tmp);
  }

  // two-center
  REP (i, s.length()) {
    int l = i;
    int r = i + 1;

    int tmp = 0;
    while (l >= 0 && r < s.length()) {
      if (s[l] == s[r])
        tmp += 2;
      --l, ++r;
    }
    ret = max(ret, tmp);
  }

  cout << ret << endl;
  
  return 0;
}