#include <algorithm>

    #include  <iterator>

    #include  <iostream>

    #include   <cstring>

    #include   <cstdlib>

    #include   <iomanip>

    #include    <bitset>

    #include    <cctype>

    #include    <cstdio>

    #include    <string>

    #include    <vector>

    #include     <cmath>

    #include     <queue>

    #include      <list>

    #include       <map>

    #include       <set>

    using namespace std;

    //#pragma GCC optimize(3)

    //#pragma comment(linker, "/STACK:102400000,102400000")  //c++

    #define lson (l , mid , rt << 1)

    #define rson (mid + 1 , r , rt << 1 | 1)

    #define debug(x) cerr << #x << " = " << x << "\n";

    #define pb push_back

    #define pq priority_queue

    typedef long long ll;

    typedef unsigned long long ull;

    typedef pair<ll ,ll > pll;

    typedef pair<int ,int > pii;

    typedef pair<int,pii> p3;

    //priority_queue<int> q;//这是一个大根堆q

    //priority_queue<int,vector<int>,greater<int> >q;//这是一个小根堆q

    #define fi first

    #define se second

    //#define endl '\n'

    #define OKC ios::sync_with_stdio(false);cin.tie(0)

    #define FT(A,B,C) for(int A=B;A <= C;++A)  //用来压行

    #define REP(i , j , k)  for(int i = j ; i <  k ; ++i)

    //priority_queue<int ,vector<int>, greater<int> >que;

    const ll mos = 0x7FFFFFFFLL;  //

    const ll nmos = 0x80000000LL;  //-2147483648

    const int inf = 0x3f3f3f3f;

    const ll inff = 0x3f3f3f3f3f3f3f3fLL; //

    const int mod = ;

    const double PI=acos(-1.0);

    // #define _DEBUG;         //*//

    #ifdef _DEBUG

    freopen("input", "r", stdin);

    // freopen("output.txt", "w", stdout);

    #endif

    /*-----------------------showtime----------------------*/

                int p[];

                char str[],t[];

                int Manacher(char *str,int len){

                    t[] = '$';t[] = '#';

                    int tot = ;

                    for(int i=; i<len; i++){

                        t[tot++]=str[i];

                        t[tot++]='#';

                    }

                    int mx = ,id = ,reslen = ,resCenter = ;

                    for(int i=; i<tot; i++){

                        if(i<mx) p[i] = min(p[*id - i] , mx - i);

                        else p[i] = ;

                        while(t[i+p[i]] == t[i-p[i]])p[i] ++;

                        if(p[i]+i > mx){

                            mx = i + p[i];

                            id = i;

                        }

                        if(reslen < p[i]){reslen = p[i], resCenter = i;}

                    }

                    return reslen;

                }

    int main(){

                while(~scanf("%s", str)){

                    int len = strlen(str);

                    printf("%d\n",Manacher(str,len)-);

                }

                return ;

    }