#include<stdio.h>
#include<string.h>
char s[2000005];
unsigned d[2000005];
int main()
{
    freopen("pscpld.in","r",stdin);
    freopen("pscpld.out","w",stdout);
    unsigned n,i,p,m=0;
    gets(s+1);
    n=strlen(s+1);
    for(i=n;i>=1;i--)
    {
    s[2*i]=s[i];
    s[2*i+1]='*';
    }
    n=2*n+1;
    s[1]='*';
    p=0;
    for(i=1;i<=n;i++)
    {
    if(i>d[p]+p)
    {
        for(d[i]=1;d[i]<i && s[i+d[i]]==s[i-d[i]] && i-d[i]>0 && i+d[i]<=n;d[i]++);
        p=i;
    }
    else
{
    if(2*p-i-d[2*p-i]>p-d[p])
    d[i]=d[2*p-i];
    else
    d[i]=p+d[p]-i;
    if(i+d[i]==p+d[p])
    {
        for(;s[i-d[i]]==s[i+d[i]] && i+d[i]<=n && i-d[i]>0;d[i]++);
        p=i;
    }
}
m=m+d[i]/2;
    }
printf("%u\n",m);
    return 0;
}