#include <bits/stdc++.h>
using namespace std;
int n;
string s;
unsigned long long f[5000005], g[5000005], p[5000005];
int main() 
{
    p[0] = 1;
    cin >> n >> s;
    for (int i = 1; i <= n; i++) p[i] = p[i-1] * 131;
    for (int i = 1; i <= n; i++) f[i] = f[i-1] * 131 + (s[i-1] - '0');
    for (int i = n; i >= 1; i--) g[i] = g[i+1] * 131 + ((s[i-1] - '0') ^ 1);
    unsigned long long cnt = 0;
    for (int i = 1; i <= n; i++) 
    {
        int l = 0, r = min(i-1, n-i);
        while (l < r) 
        {
            int mid = (l + r + 1) / 2;
            if (f[i] - f[i-mid] * p[mid] == g[i+1] - g[i+1+mid] * p[mid]) 
            {
                l = mid;
            } 
            else 
            {
                r = mid - 1;
            }
        }
        cnt += l;
    }
    cout << cnt << endl;
    return 0;
}