#include<iostream>
#include<math.h>
#include<vector>
#include <array>
#include <algorithm>
#include <queue>
#include <numeric>
#include <map>

using namespace std;
#define int long long
#define FOR(i, a, b) for(int i=(a);i<(b);i++)
#define RFOR(i, a, b) for(int i=(b-1);i>=(a);i--)
#define REP(i, n) for(int i=0; i<(n); i++)
#define RREP(i, n) for(int i=(n-1); i>=0; i--)
#define ALL(a) (a).begin(),(a).end()
#define UNIQUE_SORT(l) sort(ALL(l)); l.erase(unique(ALL(l)), l.end());
#define CONTAIN(a, b) find(ALL(a), (b)) != (a).end()
#define array2(type, x, y) array<array<type, y>, x>
#define vector2(type) vector<vector<type> >
#define out(...) //printf(__VA_ARGS__)

typedef pair<int, int> pos;
int pos::*x = &pos::first;
int pos::*y = &pos::second;

int dxy[] = {0, 1, 0, -1, 0};

/*================================*/

int D;
char w[14];

int maxlen(char d[14]) {
    int maxl = 0;
    int cnt = 0;
    REP(i, 14) {
        if (d[i] == 'o') {
            cnt++;
        } else {
            maxl = max(maxl, cnt);
            cnt = 0;
        }
    }
    return max(maxl, cnt);
}

// 先頭にある連休数
int toplen(char d[14]) {
    int cnt = 0;
    REP(i, 14) {
        if (d[i] == 'o') {
            cnt++;
        } else {
            return cnt;
        }
    }
    return cnt;
}

// 最後にある連休数
int lastlen(char d[14]) {
    int cnt = 0;
    REP(i, 14) {
        if (d[13 - i] == 'o') {
            cnt++;
        } else {
            return cnt;
        }
    }
    return cnt;
}


signed main()
{
    cin >> D;
    REP(i, 14) cin >> w[i];
    int maxl = maxlen(w);
    maxl = max(D + max(toplen(w), lastlen(w)), maxl);
    REP(i, 14) {
        char d[14];
        if (w[i] == 'o') continue;
        bool on = true;
        REP(j, 14) {
            d[j] = w[j];
            if (i <= j && j <= i + D - 1 && on) {
                d[j] = 'o';
                if (w[j] == 'o') {
                    on = false;
                }
            }
        }
        maxl = max(maxl, maxlen(d));
    }
    cout << maxl << endl;

    return 0;
}