#include <bits/stdc++.h>
#define rep(i, f, t) for(int i(f); i <= t; ++i)
#define re(i, t) for(int i(1); i <= t; ++i)
#define per(i, t, f) for(int i(t); i >= f; --i)
#define pe(i, t) for(int i(t); i >= 1; --i) 
#define nx(i, u) for(int i(head[u]); i; i = e[i].nxt)
typedef long long ll;
typedef unsigned long long ull; 
using namespace std;
typedef pair <int, int> pii;
#define pb push_back 
#define fi first
#define i128 __int128
#define se second
#define Ls (ix(l, mid))
#define Rs (ix(mid+1, r))
#define ix(l, r) ((l + r) | (l != r))  
#define mp(i, j) (make_pair(i, j))
//#define int long long
#define inf 0x3f3f3f3f
#define INF 0x3f3f3f3f3f3f3f3f
 
struct IO {
    #define MAXSIZE 1<<21
    #define isdigit(x) (x >= '0' && x <= '9')
    #define isspace(x) (x == ' ' || x == '\n' || x == '\r' || x == '\t')
    char ibuf[MAXSIZE], obuf[MAXSIZE], *s1, *s2, *s3, endl, blank;
    int round[10] = {0, 0, 0, 0, 0, 1, 1, 1, 1}, sta[65], precisions;
    bool fail;
    FILE *in_stream, *out_stream;
    IO(FILE *_stream = stdin, FILE *__stream = stdout) { reset(_stream,__stream); }
    #if DEBUG
    #else
        ~IO() {close();}
    #endif
    inline void reset (FILE *_stream = stdin, FILE *__stream = stdout, bool reset = true) {
        s1 = s3 = ibuf, s2 = obuf, in_stream = _stream, out_stream = __stream, fail = false;
        if(reset) { endl = '\n'; blank = ' '; precisions = 6; }
    }
    inline void flush_in() {s3 = (s1 = ibuf) + fread(ibuf, 1, MAXSIZE, in_stream); }
    inline void flush_out() { fwrite(obuf, 1, s2-obuf, out_stream), s2 = obuf; }
    inline void flush_out_with_stream() { flush_out(); fflush(out_stream); } 
    inline char get() {
        #if DEBUG  
            return getchar();
        #endif
        return s1 == s3 && (flush_in(), fail = s1 == s3) ? 0 : *s1++;
    }
    inline void put(char ch) {
        #if DEBUG
            putchar(ch);
        #else
            s2-obuf == MAXSIZE ? flush_out(), 0 : 0, *s2++=ch;
        #endif
    }
    template <class T>
    inline void read(T &x) {
        bool sign = false; char c = get(); x = 0;
        while(!isdigit(c) && c) {sign=c=='-'; c = get(); }
        while(isdigit(c)) { x = (x<<1) + (x<<3) + (c^'0'); c = get(); }
        sign ? x = ~x+1 : 0;
    }
    inline void read(double &x) {
        bool sign = false; char c = get(); x = 0;
        while(!isdigit(c) && c) { sign=c=='-'; c = get(); }
        while(isdigit(c)) { x = x * 10 + (c^'0'); c = get(); }
        if(c=='.') { c = get(); double tmp = 1; while(isdigit(c)) { tmp /= 10, x += tmp * (c^'0'); c = get(); } }
        sign ? x = -x : 0;
    }
    inline void read(long double &x) {
        bool sign = false; register char c = get(); x = 0;
        while(!isdigit(c) && c) { sign=c=='-'; c = get(); }
        while(isdigit(c)) { x = x * 10 + (c^'0'); c = get(); }
        if(c == '.') { c = get(); register long double tmp = 1; while(isdigit(c)) { tmp /= 10, x += tmp * (c^'0'); c = get(); } }
        sign ? x = -x : 0;
    }
    inline void read(char *s) {
        char c = get();
        while(isspace(c)) c = get();
        while(!isspace(c) && c) { *s++=c; c = get(); }
        *s = '\0';
    }
    inline void read(char &c) {
        do
            c = get();
        while(isspace(c));
    }
    template <class T, class ...Args>
    inline void read(T &x, Args &...args) { read(x), read(args...); }
    template <class T>
    inline void write(T x) {
        int top = 0;
        if(x<0) { put('-'); sta[top++] = ~(x%10)+1, x /= 10; x = ~x+1; }
        else sta[top++] = x%10, x /= 10;
        while(x) sta[top++] = x%10 ,x /= 10;
        while(top) put(sta[--top]^'0');
    }
    inline void write(double y) {
        int top = 0;
        if(y<0) { put('-'); y=-y; }
        int x = y; y -=x;
        write(x);
        if(y) {
            do
                sta[top++] = y*10, y = y*10 - sta[top-1];
            while(top<precisions-1);
            sta[top++] = y*10 + round[(int)((y*10-((int)(y*10)))*10)];
        }
        put('.');
        for(int i(0); i<top; ++i) put(sta[i]^'0');
        for(int i(top); i<precisions; ++i) put('0');
    }
    inline void write(long double y) {
        register int top = 0;
        if(y<0) { put('-'); y=-y; }
        int x = y; y -= x;
        write(x);
        if(y) {
            do
                sta[top++] = y*10, y = y*10 - sta[top-1];
            while(top<precisions-1);
            sta[top++] = y*10 + round[(int)((y*10-((int)(y*10)))*10)];
        }
        put('.');
        for(register int i(0); i < top; ++i) put(sta[i]^'0');
        for(register int i(top); i < precisions; ++i) put('0');
    }
    inline void write(const char ch) { put(ch); }
    inline void write(char *s) { while(*s!='\0') put(*s++); }
    inline void write(const char *s) { while(*s!='\0') put(*s++); }
    inline void write(const std::string str) { write(str.c_str()); }
    inline IO &precision(const int x) { precisions=x; return *this; }
    template <class T,class ...Args>
    inline void write(T x,Args ...args) { write(x), blank?put(blank), 0:0, write(args...); }
    template <class ...Args>
    inline void writeln(Args ...args) { write(args...), endl?put(endl), 0:0; }
    template <class T>
    inline IO &operator>>(T &x) { read(x); return *this; }
    inline IO &operator>>(IO &x) { return *this; }
    template <class T>
    inline IO &operator<<(const T x) { write(x); return *this; }
    inline IO &operator<<(IO &x) { return *this; }
    inline operator bool() { return !fail; }
    template <class T>
    inline operator T() { T x; read(x); return x; }
    inline void open(FILE *_stream=stdin,FILE *__stream=stdout) { close(), reset(_stream, __stream, false); }
    inline void close() { flush_out_with_stream(); fclose(in_stream), fclose(out_stream); }
    #define read(x) io>>x
    #define out(x) io<<x
}io;  

const int N = 1e6 + 5;

int len[N], lnk[N], nxt[N][30], siz[N];
char s[N];
int n, now;
int cnt =1, lst = 1;

int calc (int id) {
	while(s[now-len[id]-1] != s[now]) id = lnk[id];
	return id;
}

void ins (int c) {
	int p = calc(lst);
	if(!nxt[p][c]) {
		int cur = ++cnt;
		len[cur] = len[p] + 2;
		lnk[cur] = nxt[calc(lnk[p])][c];
		nxt[p][c] = cur;
	}
	lst = nxt[p][c];
	++siz[lst];
}

int a[N], b[N];

int main () {
	scanf("%s", s + 1);
	n = strlen(s + 1);
	len[0] = 0; lnk[0] = 1; len[1] = -1;
	for(now = 1; now <= n; ++now) {
		ins(s[now] - 'a');
	}
	rep(i, 2, cnt) ++a[len[i]];
	re(i, n) a[i] += a[i-1];
	rep(i, 2, cnt) b[a[len[i]]--] = i;
	ll ans = 0;
	pe(i, cnt-1) {
		int u = b[i];
		siz[lnk[u]] += siz[u];
		ans = max(ans, 1ll * len[u] * siz[u] * len[u]);
	}
	io << ans;
}