#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 6e5+1;
const int K = 21;
vector<int> sort_cyclic_shifts(string const& s) {
int n = s.size();
const int alphabet = 256;
vector<int> p(n), c(n), cnt(max(alphabet, n), 0);
for (int i = 0; i < n; i++)
cnt[s[i]]++;
for (int i = 1; i < alphabet; i++)
cnt[i] += cnt[i-1];
for (int i = 0; i < n; i++)
p[--cnt[s[i]]] = i;
c[p[0]] = 0;
int classes = 1;
for (int i = 1; i < n; i++) {
if (s[p[i]] != s[p[i-1]])
classes++;
c[p[i]] = classes - 1;
}
vector<int> pn(n), cn(n);
for (int h = 0; (1 << h) < n; ++h) {
for (int i = 0; i < n; i++) {
pn[i] = p[i] - (1 << h);
if (pn[i] < 0)
pn[i] += n;
}
fill(cnt.begin(), cnt.begin() + classes, 0);
for (int i = 0; i < n; i++)
cnt[c[pn[i]]]++;
for (int i = 1; i < classes; i++)
cnt[i] += cnt[i-1];
for (int i = n-1; i >= 0; i--)
p[--cnt[c[pn[i]]]] = pn[i];
cn[p[0]] = 0;
classes = 1;
for (int i = 1; i < n; i++) {
pair<int, int> cur = {c[p[i]], c[(p[i] + (1 << h)) % n]};
pair<int, int> prev = {c[p[i-1]], c[(p[i-1] + (1 << h)) % n]};
if (cur != prev)
++classes;
cn[p[i]] = classes - 1;
}
c.swap(cn);
}
return p;
}
vector<int> suffix_array_construction(string s) {
s += "$";
vector<int> sorted_shifts = sort_cyclic_shifts(s);
sorted_shifts.erase(sorted_shifts.begin());
return sorted_shifts;
}
vector<int> manacher_odd(string s) {
int n = s.size();
s = "$" + s + "^";
vector<int> p(n + 2);
int l = 1, r = 1;
for(int i = 1; i <= n; i++) {
p[i] = max(0, min(r - i, p[l + (r - i)]));
while(s[i - p[i]] == s[i + p[i]]) {
p[i]++;
}
if(i + p[i] > r) {
l = i - p[i], r = i + p[i];
}
}
return vector<int>(begin(p) + 1, end(p) - 1);
}
vector<int> manacher(string s) {
string t;
for(auto c: s) {
t += string("#") + c;
}
auto res = manacher_odd(t + "#");
return res;
}
vector<int> lcp_construction(string const& s, vector<int> const& p) {
int n = s.size();
vector<int> rank(n, 0);
for (int i = 0; i < n; i++)
rank[p[i]] = i;
int k = 0;
vector<int> lcp(n-1, 0);
for (int i = 0; i < n; i++) {
if (rank[i] == n - 1) {
k = 0;
continue;
}
int j = p[rank[i] + 1];
while (i + k < n && j + k < n && s[i+k] == s[j+k])
k++;
lcp[rank[i]] = k;
if (k)
k--;
}
return lcp;
}
ll mxr[N], xc[N], vs[N], st[K][N], lg[N];
int que(int l, int r) {
int i=lg[r-l+1];
return min(st[i][l], st[i][r-(1<<i)+1]);
}
string s;
int main() {
ios_base::sync_with_stdio(0);
cin.tie(NULL);
cout.tie(NULL);
cin>>s;
lg[1]=0;
for (int i=2; i<N; ++i) lg[i]=lg[i/2]+1;
int n=s.size();
vector<int> v=suffix_array_construction(s);
for (int i=0; i<n; ++i) vs[i+1]=v[i]+1;
vector<int> lcp=lcp_construction(s, v);
for (int i=1; i<n; ++i) st[0][i]=lcp[i-1];
for (int i=1; i<K; ++i) {
for (int j=1; j+(1<<i)<=n; ++j) {
st[i][j]=min(st[i-1][j], st[i-1][j+(1<<(i-1))]);
}
}
vector<int> x=manacher(s);
int sz=x.size();
for (int i=0; i<sz; ++i) {
if (i%2 == 1) {
ll idx=(i+1)/2, l=idx-(x[i]+1)/2+1, r=idx+(x[i]+1)/2-1;
xc[l]=max(xc[l], r-l+1);
} else {
if (i == 0 || x[i] == 1) continue;
ll idx=i/2, l=idx-x[i]/2+1, r=idx+x[i]/2;
xc[l]=max(xc[l], r-l+1);
}
}
int val=0, j=0;
for (int i=1; i<=n; ++i) {
if (xc[i] >= val-2*(i-j)) val=xc[i], j=i;
xc[i]=val-2*(i-j);
}
ll ans=0;
for (int i=1; i<=n; ++i) {
ans=max(ans, xc[vs[i]]);
int lf=1, rf=i-1, l=i, r=i-1;
while (lf <= rf) {
int m=(lf+rf)/2;
if (que(m, i-1) >= xc[vs[i]]) rf=m-1, l=m;
else lf=m+1;
}
lf=i, rf=n-1;
while (lf <= rf) {
int m=(lf+rf)/2;
if (que(i, m) >= xc[vs[i]]) lf=m+1, r=m;
else rf=m-1;
} ++r;
ans=max(ans, 1ll*(r-l+1)*xc[vs[i]]);
} cout<<ans<<"\n";
}
