#include <iostream>
#include <fstream>
#include <cstring>
using namespace std;
ifstream fin("pscpld.in");
ofstream fout("pscpld.out");
#define MAX 1001000
#define mx id+p[id]
char a[MAX], s[2*MAX+1];
int p[2*MAX+1];
int i, S;
int main()
{
    fin>>a;
    s[0]='&';
    s[1]='#';

    for(i=0;a[i]!='\0';i++)
    {
        s[2*i+2]=a[i];
        s[2*i+3]=s[1];
    }
    int id=0;
    p[id]=0;
    for (i = 1; s[i] != '\0'; i++) {
        p[i] = mx > i ? min(p[2*id-i], mx-i) : 1;
        while (s[i + p[i]] == s[i - p[i]]) p[i]++;
        if (i + p[i] > mx) {
            id = i;
    }
}

    for(i=1;s[i]!='\0';i++)
    {
        S+=p[i]/2;
    }
    fout<<S;
}