#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 1e5 + 5;
ll add[N][26];
ll prv[N][26];
int main(){
ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
string s; cin >> s;
int n = s.length();
ll cnt = 0;
for(int i = 0; i < n; ++i){
int l = i, r = i;
int cur_cnt = 0;
while(l >= 0 && r < n && s[l] == s[r]){
++cur_cnt;
--l; ++r;
}
cnt += cur_cnt;
int cur_l = l, cur_r = r;
cur_cnt = 0;
while(cur_l + 2 < cur_r){
++cur_l; --cur_r;
++cur_cnt;
prv[cur_l][s[cur_l] - 'a'] += cur_cnt;
prv[cur_r][s[cur_r] - 'a'] += cur_cnt;
}
int lf = l, rg = r;
int cnt_add = 0;
while(l >= 0 && r < n){
--l; ++r;
++cnt_add;
if(s[l] != s[r])break;
}
if(cnt_add){
add[lf][s[rg] - 'a'] += cnt_add;
add[rg][s[lf] - 'a'] += cnt_add;
}
}
for(int i = 1; i < n; ++i){
int l = i - 1, r = i;
int cur_cnt = 0;
while(l >= 0 && r < n && s[l] == s[r]){
++cur_cnt;
--l; ++r;
}
cnt += cur_cnt;
int cur_l = l, cur_r = r;
cur_cnt = 0;
while(cur_l + 2 < cur_r){
++cur_l; --cur_r;
++cur_cnt;
prv[cur_l][s[cur_l] - 'a'] += cur_cnt;
prv[cur_r][s[cur_r] - 'a'] += cur_cnt;
}
int lf = l, rg = r;
int cnt_add = 0;
while(l >= 0 && r < n){
--l; ++r;
++cnt_add;
if(s[l] != s[r])break;
}
if(cnt_add){
add[lf][s[rg] - 'a'] += cnt_add;
add[rg][s[lf] - 'a'] += cnt_add;
}
}
ll max_add = 0;
for(int i = 0; i < n; ++i){
for(int j = 0; j < 26; ++j){
max_add = max(max_add, add[i][j] - prv[i][s[i] - 'a']);
}
}
cout << cnt + max_add << '\n';
return 0;
}
