#include <bits/stdc++.h>
using namespace std;
typedef unsigned long long ull;
int n;
ull x[500005];
ull sum[500005], sum2[500005], power[500005], b = 29, ans;
ull a[500005];
char c;
bool check(int s, int t) {
    ull o = sum[s + t] - sum[s - t] * power[2 * t];
    ull p = sum2[n - s + t] - sum2[n - s - t] * power[2 * t];

    if (o + p == x[2 * t])
        return true;
    else
        return false;
}
int main() {
    scanf("%d", &n);

    for (int i = 1; i <= n; i++) {
        cin >> c;

        if (c == '0')
            a[i] = 0;
        else
            a[i] = 1;
    }

    power[0] = 1;
    x[0] = 0;

    for (int i = 1; i <= 500000; i++) {
        power[i] = b * power[i - 1];
        x[i] = x[i - 1] * b + 1;
    }

    for (int i = 1; i <= n; i++) {
        sum[i] = b * sum[i - 1] + a[i];
        sum2[i] = b * sum2[i - 1] + a[n + 1 - i];
    }

    for (int i = 1; i <= n - 1; i++) {
        int l = 1, r = min(i, n - i);

        while (l <= r) {
            int mid = (l + r) / 2;

            if (check(i, mid))
                l = mid + 1;
            else
                r = mid - 1;
        }

        ans += r;
    }

    printf("%lld", ans);
    return 0;
}