#include<iostream>
#include<string>
using namespace std;
string s;
int min(int a, int b)
{
return a>b ? b : a;
}
int max(int a, int b)
{
return a>b ? a : b;
}
int Manacher()
{
if(s.length() == 0) return 0;
int len = (int)(s.length()*2+1);
char *cArry = new char[len];
int *pArry = new int[len];
for(int i = 0; i < len; i++)
cArry[i] = i&1 ? s[(i-1)/2] : '#';
int R = -1;
int C = -1;
int maxn = 0;
for(int i = 0; i < len; i++)
{
pArry[i] = i > R ? 1 : min(pArry[2*C-i], R-i);
while(i+pArry[i] < len && i-pArry[i] > -1)
{
if(cArry[i+pArry[i]] == cArry[i-pArry[i]]) pArry[i]++;
else break;
}
if(i+pArry[i] > R)
{
R = i+pArry[i];
C = i;
}
maxn = max(maxn, pArry[i]);
}
delete[] cArry;
delete[] pArry;
return maxn-1;
}
int main()
{
while(getline(cin, s))
if(s.length() != 0)
printf("%d\n", Manacher());
getchar();
return 0;
}