#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
const int N=2e6+5;
int n, f[N], q[N];
char s[N];
int main()
{
    scanf("%d%s", &n, s+1);
    LL ans=0;
    memset(f, 0, sizeof(f));
    for(int i=1; i<=n; i++)
    {
        q[i] = i-1;
        while(q[i] > 0 && s[q[i]] != s[i])
        {
            q[i] = q[q[i]] - 1;}
        if(q[i] > 0) f[i] = f[q[i]-1] + 1;
        ans += f[i];
    }
    printf("%lld\n", ans);
    return 0;
}

#include<bits/stdc++.h>
using namespace std;
typedef long long LL;
const int N=2e6+5;
int n,f[N],q[N];
char s[N];
LL ans;
int main()
{
    scanf("%d%s",&n,s+1);
    LL ans=0;
    memset(f,0,sizeof(f));
    for(int i=1;i<=n;i++)
    {
        q[i]=i-1;
        while(q[i]>0 && s[q[i]]!=s[i])
		{
			q[i]=q[q[i]]-1;
		}
        if(q[i]>0) f[i]=f[q[i]-1]+1;
		ans+=f[i];
    }
    printf("%lld\n",ans);
    return 0;
}