#include <string>
#include <vector>
#include <iostream>

using namespace std;
int main()
{
    string s;
    cin >> s;
    {
        vector<char> t;
        t.push_back(' ');
        for(char c:s)
        {
            t.push_back(c);
            t.push_back(' ');
        }
        s= string(t.begin(),t.end());
    }
    int n= (int)s.size();
    vector<int> ro(n, 1);
    int left=0,right=0;
    for(int i=1; i<n; i++)
    {
        int L,R;
        if(i > right)
        {
            L = i;
            R = i;
        }
        else
        {
            int mi= right+left-i;
            L= i-ro[mi]+1;
            R= i+ro[mi]-1;
            if(R > right)
            {
                int d= R-right;
                R = R-d;
                L = L+d;
            }
        }
        while(L-1>=0 && R+1<n && s[L-1] == s[R+1])
        {
            L--; R++;
        }
        ro[i] = R-i+1;
        if(R > right)
        {
            left = L;
            right = R;
        }
    }
    long long c = 0;
    for(int &value:ro) c += value/2;
    cout << c;
    return 0;
}