#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (n); i++)
using namespace std;
using ll = long long;
using P = pair<int, int>;

int main() {
    ll n;
    cin >> n;
    string s;
    cin >> s;
    reverse(s.begin(), s.end());
    s += '.';

    int idx = 0;
    rep(i, n) {
        if (s[i] == '#') idx = i;
    }

    ll add = 0;
    rep(i, idx) {
        if (s[i] == '#' && s[i + 1] == '#') add++;
        if (s[i] == '.' && s[i + 1] == '.' && add > 0) add--;
    }

    cout << idx + 1 + add << endl;
}