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

#define rep(i, a, b) for (int i = a; i < b; i++)
using ll = long long;

int main(){
    int n;
    string s;
	cin >> n >> s;
    using P = pair<char, int>;
    vector<P> p;
    rep(i, 0, n) {
        if(p.size() && p.back().first == s[i]) p.back().second++;
        else p.emplace_back(s[i], 1);
    }
    int ma = 0, sz = p.size();
    rep(i, 0, sz) {
        if(p[i].first == '.') {
            if(i == 0 || i == sz - 1) ma = max(ma, p[i].second);
            else ma = max(ma, (p[i].second + 1) / 2);
        }
    }
    int ans = 0;
    rep(i, 0, sz) {
        if(p[i].first == '.') {
            if(i == 0 && p[i].second == ma) {
                ans = 1;
                break;
            }
            if(i == sz - 1 && p[i].second == ma) {
                ans = n;
                break;
            }
            if((p[i].second + 1) / 2 == ma) {
                ans += (p[i].second + 1) / 2;
                break;
            }
            ans += p[i].second;
        }
        else ans += p[i].second;
    }
    cout << ans << endl;
}