@

#include <iostream>
using namespace std;

#define MAXN 2000006

using ll = long long;

char ch[MAXN];

int las[MAXN];
int cnt[MAXN];

int main()
{
	int n;
	cin >> n;
	ll res = 0;
	for (int i = 1; i <= n; i++)
	{
		cin >> ch[i];
		int j = i - 1;
		while (j > 0 && ch[j] != ch[i])
		{
			j = las[j] - 1;
		}
		las[i] = j;
		if (j > 0)
		{
			res += cnt[i] = cnt[j - 1] + 1;
		}
	}
	cout << res << endl;
	return 0;
}