/**************************************************************

     Problem: 2084

     User: Tunix

     Language: C++

     Result: Accepted

     Time:68 ms

     Memory:9572 kb

 ****************************************************************/

 //BZOJ 2084

 #include<vector>

 #include<cstdio>

 #include<cstring>

 #include<cstdlib>

 #include<iostream>

 #include<algorithm>

 #define rep(i,n) for(int i=0;i<n;++i)

 #define F(i,j,n) for(int i=j;i<=n;++i)

 #define D(i,j,n) for(int i=j;i>=n;--i)

 #define pb push_back

 using namespace std;

 typedef long long LL;

 inline int getint(){

     int r=,v=; char ch=getchar();

     for(;!isdigit(ch);ch=getchar()) if(ch=='-')r=-;

     for(; isdigit(ch);ch=getchar()) v=v*+ch-'';

     return r*v;

 }

 const int N=5e5+,INF=~0u>>;

 /*******************template********************/

 char s[N];

 int a[N<<],p[N<<];

 int main(){

     int n=getint();

     scanf("%s",s);

     F(i,,n) a[i<<]=s[i-];

     n=n<<|;

     int id=,ans=;

     F(i,,n){

         if (a[i]!=) continue;

         if (p[id]+id>i) p[i]=min(p[*id-i],p[id]+id-i);

         else p[i]=;

         while(i-p[i]-> && i+p[i]+<=n &&

             (a[i-p[i]-]!=a[i+p[i]+] || a[i-p[i]-]==))p[i]++;

         if (p[i]+i>p[id]+id) id=i;

         ans+=p[i];

     }

     printf("%d\n",ans/);

     return ;

 }