#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,j,dr,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]='*';
    dr=0;
    p=0;
    for(i=1;i<=n;i++)
    {
    if(i>dr)
    {
        for(j=1;j<i && s[i+j]==s[i-j] && i-j>0 && i+j<=n;j++);
        dr=j+i-1;
        p=i;
        d[i]=j;
    }
    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]==dr+1)
    {
        for(j=1;j<=n && s[i-d[i]-j+1]==s[dr+j] && dr+j<=n && i-d[i]-j+1>0;j++);
        d[i]=d[i]+j-1;
        dr=i+d[i]-1;
        p=i;
    }
}
m=m+d[i]/2;
    }
printf("%u ",m);
    return 0;
}