/* 3068 */

 #include <iostream>

 #include <string>

 #include <map>

 #include <queue>

 #include <set>

 #include <stack>

 #include <vector>

 #include <deque>

 #include <algorithm>

 #include <cstdio>

 #include <cmath>

 #include <ctime>

 #include <cstring>

 #include <climits>

 #include <cctype>

 #include <cassert>

 #include <functional>

 using namespace std;

 //#pragma comment(linker,"/STACK:102400000,1024000")

 #define sti                set<int>

 #define stpii            set<pair<int, int> >

 #define mpii            map<int,int>

 #define vi                vector<int>

 #define pii                pair<int,int>

 #define vpii            vector<pair<int,int> >

 #define rep(i, a, n)     for (int i=a;i<n;++i)

 #define per(i, a, n)     for (int i=n-1;i>=a;--i)

 #define clr                clear

 #define pb                 push_back

 #define mp                 make_pair

 #define fir                first

 #define sec                second

 #define all(x)             (x).begin(),(x).end()

 #define SZ(x)             ((int)(x).size())

 #define lson            l, mid, rt<<1

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

 const int maxn = ;

 char s[maxn*], ss[maxn];

 int P[maxn*];

 int ans, l;

 void init() {

     int i, len = strlen(ss);

     l = ;

     s[l++] = '@';

     s[l++] = '#';

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

         s[l++] = ss[i];

         s[l++] = '#';

     }

     s[l++] = '\0';

 }

 void manacher() {

     int i, mx = , id;

     for (i=; i<l; ++i) {

         P[i] = mx>i ? min(P[*id-i], mx-i) : ;

         while (s[i+P[i]] == s[i-P[i]])

             ++P[i];

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

             mx = i + P[i];

             id = i;

         }

     }

     ans = ;

     for (i=; i<l; ++i)

         ans = max(ans, P[i]);

     printf("%d\n", ans-);

 }

 void solve() {

     init();

     manacher();

 }

 int main() {

     ios::sync_with_stdio(false);

     #ifndef ONLINE_JUDGE

         freopen("data.in", "r", stdin);

         freopen("data.out", "w", stdout);

     #endif

     while (scanf("%s", ss)!=EOF) {

         solve();

     }

     #ifndef ONLINE_JUDGE

         printf("time = %d.\n", (int)clock());

     #endif

     return ;

 }