#include <iostream>
#include <vector>
#include <cmath>

using namespace std;

int main() {

    int nmbTiles;
    string input;

    cin >> nmbTiles;
    cin >> input;

//    vector<int> xCount;
//    vector<int> oCount;
//    int xSum = 0;
//    int oSum = 0;
//    xCount.push_back(xSum);
//    oCount.push_back(oSum);
//    for (int i = 0; i < input.size(); i++) {
//        if (input[i] == 'X') {
//            xSum++;
//        } else {
//            oSum++;
//        }
//        xCount.push_back(xSum);
//        oCount.push_back(oSum);
//    }
//
//    int out = 0;
//    for (int right = 0; right <= input.size(); right++) {
//        for (int left = 0; left < right; left++) {
//            int xInside = xCount[right] - xCount[left];
//            int oInside = oCount[right] - oCount[left];
//
//            int n = (int)sqrt(oInside);
//            if (n * n != oInside || oInside == 0) {
//                continue; // skip if O is not n^2
//            }
//
////            int xExpected = 4 * n + 4;
////            int oExpected = n * n;
////            if (xInside < xExpected || oInside < oExpected) {
////                break;
////            }
//
//            if (xInside == 4 * n + 4) {
//                out++;
//            }
//        }
//    }
//    cout << out << endl;

    int out = 0;
    for (int i = 0; i < input.size(); i++) {
        for (int j = 0; j < i; j++) {

            int xCount = 0, oCount = 0;
            for (int k = j; k <= i; k++) {
                if (input[k] == 'X') {
                    xCount++;
                } else {
                    oCount++;
                }
            }

            int n = (int)sqrt(oCount);
            if (n * n != oCount || oCount == 0) {
                continue; // skip if O is not n^2
            }

            if (xCount >= 4 * n + 4) {
                out++;
            }
        }
    }

    cout << out << endl;
    return 0;
}