#include <algorithm>
#include <cstdio>
#include <iostream>
#include <map>
#include <cmath>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
#include <stdlib.h>
#include <stdio.h>
#include <bitset>
#include <cstring>
#include <deque>
using namespace std;
#define FOR(I,A,B) for(int I = (A); I < (B); ++I)
#define CLR(mat) memset(mat, 0, sizeof(mat))
typedef long long ll;
int main()
{
  ios::sync_with_stdio(false);
  cin.tie(0);
  string s; cin >> s;
  int ans = 0;
  FOR(i,0,s.length()) {
    // 奇数
    int cnt1 = 1, l = i - 1, r = i + 1;
    while(l >= 0 && r < s.length()) {
      if(s[l] == s[r]) cnt1 += 2;
      l--;
      r++;
    }
    int cnt2 = 0;
    l = i, r = i + 1;
    while(l >= 0 && r < s.length()) {
      if(s[l] == s[r]) cnt2 += 2;
      l--;
      r++;
    }
    ans = max(ans, max(cnt1, cnt2));
  }
  cout << ans << endl;
  return 0;
}