#include <iostream>
#include <algorithm>
#include <vector>
#include <string.h>
using namespace std;
template<class T> inline void YES(T condition){ if(condition) cout << "YES" << endl; else cout << "NO" << endl; }
template<class T> inline void Yes(T condition){ if(condition) cout << "Yes" << endl; else cout << "No" << endl; }
template<class T> inline void POSS(T condition){ if(condition) cout << "POSSIBLE" << endl; else cout << "IMPOSSIBLE" << endl; }
template<class T> inline void Poss(T condition){ if(condition) cout << "Possible" << endl; else cout << "Impossible" << endl; }
template<class T> inline void First(T condition){ if(condition) cout << "First" << endl; else cout << "Second" << endl; }
template<class T = string, class U = char>int character_count(T text, U character){ int ans = 0; for(U i: text){ ans += (i == character); } return ans; }
long power(long base, long exponent, long module){ if(exponent % 2){ return power(base, exponent - 1, module) * base % module; }else if(exponent){ long root_ans = power(base, exponent / 2, module); return root_ans * root_ans % module; }else{ return 1; }}
struct position{ int y, x; }; position move_pattern[4] = {{-1, 0}, {0, 1}, {1, 0}, {0, -1}}; // double euclidean(position first, position second){ return sqrt((second.x - first.x) * (second.x - first.x) + (second.y - first.y) * (second.y - first.y)); }
template<class T, class U> string to_string(pair<T, U> x){ return to_string(x.first) + "," + to_string(x.second); }
template<class itr> void array_output(itr start, itr goal){ string ans; for(auto i = start; i != goal; i++){ ans += to_string(*i) + " "; } ans.pop_back(); cout << ans << endl; }
template<class itr> void cins(itr start, itr goal){ for(auto i = start; i != goal; i++){ cin >> (*i); } }
template<class T> T gcd(T a, T b){ if(a && b){ return gcd(min(a, b), max(a, b) % min(a, b)); }else{ return a; }} template<class T> T lcm(T a, T b){ return a / gcd(a, b) * b; }
#define mod long(1e9 + 7)
#define all(x) (x).begin(), (x).end()
#define bitcount(n) __builtin_popcountl(long(n))
#define fcout cout << fixed << setprecision(10)
#define highest(x) (63 - __builtin_clzl(x))
struct combination{ vector<long> fact, inv; combination(int sz) : fact(sz + 1), inv(sz + 1){ fact[0] = 1; for(int i = 1; i <= sz; i++){ fact[i] = fact[i - 1] * i % mod; } inv[sz] = power(fact[sz], mod - 2, mod); for(int i = sz - 1; i >= 0; i--){ inv[i] = inv[i + 1] * (i + 1) % mod; } } long C(int p, int q) const{ if(q < 0 || p < q) return 0; return (fact[p] * inv[q] % mod * inv[p - q] % mod); } };

const int _base = 1e9 + 7;

struct RollingHash
{
    vector< unsigned > hashed, power;
    RollingHash(const string& s)
    {
        int sz = s.size();
        hashed.assign(sz + 1, 0);
        power.assign(sz + 1, 0);
        
        power[0] = 1;
        for(int i = 0; i < sz; i++) {
            power[i + 1] = power[i] * _base;
        }
        for(int i = 0; i < sz; i++) {
            hashed[i + 1] = (hashed[i] + s[i]) * _base;
        }
    }
    unsigned get(int l, int r) // [l, r)
    {
        return((hashed[r] - hashed[l] * power[r - l]));
    }
    unsigned rev(int l, int r){
        return get(hashed.size() - 1 - r, hashed.size() - 1 - l);
    }
    unsigned connect(int h1, int h2, int h2len)
    {
        return(h1 * power[h2len] + h2);
    }
    int LCP(RollingHash& b, int l1, int r1, int l2, int r2)
    {
        int len = min(r1 - l1, r2 - l2);
        int low = -1, high = len + 1;
        while(high - low > 1) {
            int mid = (low + high) >> 1;
            if(get(l1, l1 + mid) == b.get(l2, l2 + mid)) low = mid;
            else high = mid;
        }
        return(low);
    }
};

int size;
RollingHash hashed(""), reversed("");

int palindrome(int left_r, int right_l){
    int left = 0, right = min(left_r, size - right_l) + 1; // [left, right)
    while(left + 1 < right){
        int middle = (left + right) / 2;
        if(hashed.get(left_r - middle, left_r) == reversed.rev(right_l, right_l + middle)){
            left = middle;
        }else{
            right = middle;
        }
    }
    return left;
}

int main(){
    string S;
    cin >> S;
    size = int(S.size());
    hashed = RollingHash(S);
    reverse(all(S));
    reversed = RollingHash(S);
    int ans = 0;
    for(int i = 0; i < size; i++){
        int normal_ans = palindrome(i, i + 1);
        ans = max({ans, normal_ans * 2 + palindrome(i - normal_ans - 1, i + 1 + normal_ans) * 2 + 1, normal_ans * 2 + palindrome(i - normal_ans, i + 2 + normal_ans) * 2 + 1});
    }
    for(int i = 0; i < size - 1; i++){
        int normal_ans = palindrome(i + 1, i + 1);
        ans = max({ans, normal_ans * 2 + palindrome(i - normal_ans, i + 1 + normal_ans) * 2, normal_ans * 2 + palindrome(i + 1 - normal_ans, i + 2 + normal_ans) * 2});
    }
    if(ans == size){
        cout << size - 1 << endl;
    }else{
        cout << ans << endl;
    }
}