maximum substring/subsequence palindrome length(dp)

//substring

#include <bits/stdc++.h>
using namespace std;
#define ll long long int
const int mod = 1000000007;
const int mx = 1005;
int dp[mx][mx];
string s;
ll solve(int b, int e) {
  if (b >= e) {
    return 1;
  }
  if (dp[b][e] != -1) {
    return dp[b][e];
  }
  if (s[b] == s[e]) {
    return dp[b][e] = solve(b + 1, e - 1);
  } else {
    return dp[b][e] = 0;
  }
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  memset(dp, -1, sizeof(dp));
  cin >> s;
  int res = -1;
  for (int i = 0; i < s.size() ; i++) {
    for (int j = i; j < s.size(); j++) {
      if (solve(i, j)) {
        // cout << i << " " << j << endl;
        res = max(res, j - i + 1);
      }
    }
  }
  cout << res << endl;
  return 0;
}








//subsequence

#include <bits/stdc++.h>
using namespace std;
#define ll long long int
const int mod = 1000000007;
const int mx = 1005;
int dp[mx][mx];
string s;
pair<int,int>nxt[mx][mx];
ll solve(int b, int e) {
  if (b == e) {
    return 1;
  }
  if (b > e) {
    return 0;
  }
  if (dp[b][e] != -1) {
    return dp[b][e];
  }
  if (s[b] == s[e]) {
    nxt[b][e]={b+1,e-1};
    return dp[b][e] = solve(b + 1, e - 1) + 2;
  } else {
    int val1 = solve(b + 1, e);
    int val2 = solve(b, e - 1);
    if(val1>val2){
      nxt[b][e]={b+1,e};
    }else{
      nxt[b][e]={b,e-1};
    }
    return dp[b][e] = max(val1, val2);
  }
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  memset(dp, -1, sizeof(dp));
  cin >> s;
  // int res = -1;
  // for (int i = 0; i < s.size(); i++) {
  //   for (int j = i; j < s.size(); j++) {
  //     if (solve(i, j)) {
  //       // cout << i << " " << j << endl;
  //       res = max(res, j - i + 1);
  //     }
  //   }
  // }
  cout << solve(0, s.size() - 1) << endl;
  return 0;
}