#include<bits/stdc++.h>

 using namespace std;

 typedef unsigned int ui;

 typedef long long ll;

 typedef unsigned long long ull;

 #define pf printf

 #define mem(a,b) memset(a,b,sizeof(a))

 #define prime1 1e9+7

 #define prime2 1e9+9

 #define pi 3.14159265

 #define lson l,mid,rt<<1

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

 #define scand(x) scanf("%llf",&x)

 #define f(i,a,b) for(int i=a;i<=b;i++)

 #define scan(a) scanf("%d",&a)

 #define dbg(args) cout<<#args<<":"<<args<<endl;

 #define inf 0x3f3f3f3f

 #define maxn 110005

 int n,m,t;

 char s[maxn];

 char tmp[maxn<<];

 int l[maxn<<];//转换后的字符串以及最大回文半径

 int manacher(char *st,int len)

 {

     int t=;

     tmp[t++]='$';

     tmp[t++]='#';

     f(i,,len-)

     {

         tmp[t++]=s[i];

         tmp[t++]='#';

     }

     tmp[t]=;

     int mr=,ans=,pos=;//最长回文右端、最长回文长度以及回文中心

     f(i,,t-)

     {

         l[i]=mr>i?min(mr-i,l[*pos-i]):;

         //i>=mr时需要以i为新的回文中心开始搜索回文长度

         while(tmp[i-l[i]]==tmp[i+l[i]])l[i]++;

         if(i+l[i]>mr)//更新最大回文右端点

         {

             mr=i+l[i];

             pos=i;

         }

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

     }

     return ans-;//每次回文串长度为2*k+1时，多余字符为k+1个，有k个属于原串的字符

 }

 int main()

 {

     //freopen("input.txt","r",stdin);

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

     std::ios::sync_with_stdio(false);

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

     {

         int len=strlen(s);

         pf("%d\n",manacher(tmp,len));

     }

  }