#pragma GCC target("sse,sse2,sse3,ssse3,sse4,avx,avx2")
#include <bits/stdc++.h>
#define pb push_back
#define all(v) (v).begin(), (v).end()
#define rep(i, n) for (int i = 0; i < n; ++i)
#define rrep(i, n) for (int i = 1; i <= n; ++i)
#define ff first
#define ss second
using namespace std;
typedef long long ll;
void __print(int x) { cerr << x; }
void __print(long x) { cerr << x; }
void __print(long long x) { cerr << x; }
void __print(unsigned x) { cerr << x; }
void __print(unsigned long x) { cerr << x; }
void __print(unsigned long long x) { cerr << x; }
void __print(float x) { cerr << x; }
void __print(double x) { cerr << x; }
void __print(long double x) { cerr << x; }
void __print(char x) { cerr << '\'' << x << '\''; }
void __print(const char *x) { cerr << '\"' << x << '\"'; }
void __print(const string &x) { cerr << '\"' << x << '\"'; }
void __print(bool x) { cerr << (x ? "true" : "false"); }
template <typename T, typename V> void __print(const pair<T, V> &x) {
cerr << '{';
__print(x.first);
cerr << ", ";
__print(x.second);
cerr << '}';
}
template <typename T> void __print(const T &x) {
int f = 0;
cerr << '{';
for (auto &i : x)
cerr << (f++ ? ", " : ""), __print(i);
cerr << "}";
}
void _print() { cerr << "]\n"; }
template <typename T, typename... V> void _print(T t, V... v) {
__print(t);
if (sizeof...(v))
cerr << ", ";
_print(v...);
}
#ifdef LOCAL
#define dbg(x...) \
cerr << "\e[91m" << __func__ << ":" << __LINE__ << " [" << #x << "] = ["; \
_print(x); \
cerr << "\e[39m" << endl;
#else
#define dbg(x...)
#endif
const int MAXN = 600100;
int a[MAXN*2];
int lcp[MAXN],sfx[MAXN],ord[MAXN],nord[MAXN],p,n,rev[MAXN];
string s;
void manacher(string s){
int k=-1,r=-1;
int n = s.size();
for(int i=0; i<n; i++){
if(i<r) a[i] = min(a[2*k-i],r-i);
while(i-a[i]-1>=0 && i+a[i]+1<n && s[i-a[i]-1]==s[i+a[i]+1]) a[i]++;
if(i+a[i]>r) r=i+a[i],k=i;
}
rep(i,n) a[i] = a[i]-i;
}
struct shit_{
int v[MAXN*4] = {};
void build(int node, int s, int e){
if(s==e) {
v[node] = a[s]; return;
}
int m = s+e>>1;
build(2*node,s,m); build(node*2+1,m+1,e);
v[node] = max(v[node*2],v[node*2+1]);
}
int query(int node, int s, int e, int l, int r, int k){
// a[x]>=k 인 최대의 x
//dbg(node,s,e,l,r,v[node],k)
if(v[node]<k) return -1;
int m = s+e>>1;
if(r<s||l>e) return -1;
if(s==e) return s;
int rr = query(2*node+1,m+1,e,l,r,k);
if(rr!=-1) return rr;
return query(2*node,s,m,l,r,k);
}
int query(int i, int j){
int xx = query(1,0,n*2-1,2*i,i+j,-2*i);
return xx-i*2+1;
}
}shit;
bool cmp(int i, int j){
if(ord[i]!=ord[j]) return ord[i] < ord[j];
i += p; j+= p;
return (i<n && j<n) ? ord[i] < ord[j] : i>j;
}
int cnt[MAXN];
void fuck(){
rep(i,n) ord[i] = s[i], sfx[i] = i;
p = 1; int pcnt=0;
while(1){
memset(cnt,0,sizeof(cnt));
for(int i=0; i<n; i++) cnt[ord[min(i+p,n)]]++;
for(int i=1; i<=n || i<256; i++) cnt[i] += cnt[i-1];
for(int i=0; i<n; i++) nord[--cnt[ord[min(i+p,n)]]] = i;
memset(cnt,0,sizeof(cnt));
for(int i=0; i<n; i++) cnt[ord[i]]++;
for(int i=1; i<=n || i<256; i++) cnt[i] += cnt[i-1];
for(int i=n-1; i>=0; i--) sfx[--cnt[ord[nord[i]]]] = nord[i];
if(pcnt==n-1) break;
nord[sfx[0]] = 0;
for(int i=1; i<n; i++) nord[sfx[i]] = nord[sfx[i-1]] + cmp(sfx[i-1],sfx[i]);
pcnt = nord[sfx[n-1]];
memcpy(ord,nord,sizeof(ord));
p*=2;
}
rep(i,n) rev[sfx[i]] = i;
for(int i=0,h=0; i<n; i++){
if(rev[i]!=n-1){
int nx = sfx[rev[i]+1];
while(nx+h<n && i+h<n && s[nx+h]==s[i+h]) h++;
lcp[rev[i]] = h;
}
h = max(h-1,0);
}
}
struct rmq_idx_ {
int sz = 1<<19; int tree[1<<20] = {};
void build(){
for(int i=sz; i<sz*2; i++) tree[i] = i-sz;
for(int i=sz-1; i>0; i--){
int ll = tree[i<<1], rr = tree[(i<<1)|1];
if(rr>=MAXN || ll>=MAXN) tree[i] = MAXN;
else {
tree[i] = (lcp[ll] < lcp[rr] ? ll : rr);
}
}
}
int query(int l, int r){
l = l+sz, r = r+sz;
int M = MAXN+100, ans=-1;
while(l<=r){
if(l&1){
if(lcp[tree[l]]<M) ans = tree[l], M = lcp[tree[l]];
l++;
}
if(~r&1){
if(lcp[tree[r]]<M) ans=tree[r], M = lcp[tree[r]];
r--;
}
l>>=1; r>>=1;
}
return ans;
}
}rmq_idx;
ll ans = 0;
void dnc(int s, int e){
if(s==e) return;
int pos = rmq_idx.query(s,e-1);
int st = sfx[pos], len = lcp[pos];
ans = max(ans,(ll)(e-s+1)*shit.query(st,st+len-1));
dnc(s,pos);
dnc(pos+1,e);
}
void solve(){
cin >> s;
n = s.size();
fuck();
string ss;
rep(i,n){
ss.push_back(s[i]);
ss.push_back('#');
}
manacher(ss);
rmq_idx.build();
shit.build(1,0,n*2-1);
dnc(0,n-1);
for(int i=0; i<n*2-1; i++){
int ddd = i+a[i];
if(i%2==0) ans = max(ans,(ll)(ddd/2)*2 + 1);
else ans = max(ans,(ll)((ddd+1)/2)*2);
}
cout << ans;
};
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
cout.tie(nullptr);
int t = 1;
// cin >> t;
while(t--) solve();
return 0;
}
