#include <bits/stdc++.h>
using namespace std;

int main() {
    int D;
    vector<int> holiday(14);
    cin >> D;
    for (int i = 0; i < 14; i++) {
        char c;
        cin >> c;
        if (c == 'o')
            holiday[i] = 1;
    }

    int ans = 0;
    for (int i = 0; i < 14; i++) {
        auto book = holiday;
        for (int j = i; j < min(14, i + D); j++) {
            if (book[j])
                break;
            book[j] = 1;
        }
        int now = 0;
        for (int j = 0; j < 14; j++) {
            if (book[j])
                now++;
            else
                now = 0;
            ans = max(ans, now);
        }
    }

    cout << ans << endl;
}