#include <bits/stdc++.h>

using i64 = long long;

int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
    
    int n;
    std::cin >> n;
    
    std::string s;
    std::cin >> s;
    
    i64 ans = 0;
    std::vector<int> lst(n + 1), f(n + 1);
    lst[0] = -1;
    f[0] = 0;
    for (int i = 1; i <= n; i++) {
        int j = i - 1;
        while (j > 0 && s[j - 1] != s[i - 1]) {
            j = lst[j];
        }
        lst[i] = std::max(-1, j - 1);
        f[i] = lst[i] == -1 ? 0 : f[lst[i]] + 1;
        ans += f[i];
    }
    std::cout << ans << "\n";
    
    return 0;
}