#include <cstdio>

#include <algorithm>

#define N 300010

using namespace std;

typedef long long ll;

int next[N][26] , fa[N] = {1 , 1} , len[N] = {0 , -1} , si[N] , tot = 1 , last;

char str[N];

void insert(int c , int now)

{

	int p = last;

	while(str[now - len[p] - 1] != str[now]) p = fa[p];

	if(!next[p][c])

	{

		int q = fa[p];

		while(str[now - len[q] - 1] != str[now]) q = fa[q];

		fa[++tot] = next[q][c] , next[p][c] = tot , len[tot] = len[p] + 2;

	}

	last = next[p][c] , si[last] ++ ;

}

int main()

{

	int i;

	ll ans = 0;

	scanf("%s" , str + 1);

	for(i = 1 ; str[i] ; i ++ ) insert(str[i] - 'a' , i);

	for(i = tot ; i > 1 ; i -- ) ans = max(ans , (ll)si[i] * len[i]) , si[fa[i]] += si[i];

	printf("%lld\n" , ans);

	return 0;

}