/**************************************************************
    Problem: 2084
    User: zrts
    Language: C++
    Result: Accepted
    Time:12 ms
    Memory:3248 kb
****************************************************************/
 
#include<cstdio>
using namespace std;
int n;
char a[500005];
int r[500005];
long long ans;
inline int max(int a,int b){
    if(a>b) return a;
    return b;
}
inline int min(int a,int b){
    if(a<b) return a;
    return b;
}
int main(){
    scanf("%d%s",&n,a);
    int i(0),j(0),lim=n-1,k;
    for(;i<lim;){
        while(i-j>=0&&i+j+1<n&&a[i-j]!=a[i+j+1]) j++;
        ans+=(r[i]=j);
        k=1;
        while(i>=k&&k<=j&&r[i-k]<j-k){
            ans+=(r[i+k]=min(r[i-k],j-k));
            k++;
        }
        j=max(j-k,0);i+=k;
    }
    printf("%lld\n",ans);
    return 0;
}