#include <bits/stdc++.h>
using namespace std;
template <class T>
bool chmax(T &a, const T &b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T>
bool chmin(T &a, const T &b) {
  if (b < a) {
    a = b;
    return 1;
  }
  return 0;
}
template <class T>
int former(const vector<T> &v, T x) {
  return upper_bound(v.begin(), v.end(), x) - v.begin() - 1;
}
template <class T>
int latter(const vector<T> &v, T x) {
  return lower_bound(v.begin(), v.end(), x) - v.begin();
}
long long gcd(long long a, long long b) { return b ? gcd(b, a % b) : a; }
const long long LLINF = 1LL << 60;
const int INTINF = 1 << 29;
const int MAX = 510000;
const int MOD = 1000000007;
long long fac[MAX], finv[MAX], inv[MAX];
void COMinit() {
  fac[0] = fac[1] = 1;
  finv[0] = finv[1] = 1;
  inv[1] = 1;
  for (int i = 2; i < MAX; i++) {
    fac[i] = fac[i - 1] * i % MOD;
    inv[i] = MOD - inv[MOD % i] * (MOD / i) % MOD;
    finv[i] = finv[i - 1] * inv[i] % MOD;
  }
}
long long COM(int n, int k) {
  if (n < k) return 0;
  if (n < 0 || k < 0) return 0;
  return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD;
}
struct UnionFind {
  vector<long long> par;
  UnionFind(long long n) : par(n, -1) {}
  void init(long long n) { par.assign(n, -1); }
  long long root(long long x) {
    if (par[x] < 0)
      return x;
    else
      return par[x] = root(par[x]);
  }
  bool issame(long long x, long long y) { return root(x) == root(y); }
  bool merge(long long x, long long y) {
    x = root(x);
    y = root(y);
    if (x == y) return false;
    if (par[x] > par[y]) swap(x, y);
    par[x] += par[y];
    par[y] = x;
    return true;
  }
  long long size(long long x) { return -par[root(x)]; }
};
template <typename T>
vector<T> dijkstra(int s, vector<vector<pair<int, T> > > &G) {
  const T INF = numeric_limits<T>::max();
  using P = pair<T, int>;
  int n = G.size();
  vector<T> d(n, INF);
  vector<int> b(n, -1);
  priority_queue<P, vector<P>, greater<P> > q;
  d[s] = 0;
  q.emplace(d[s], s);
  while (!q.empty()) {
    P p = q.top();
    q.pop();
    int v = p.second;
    if (d[v] < p.first) continue;
    for (auto &e : G[v]) {
      int u = e.first;
      T c = e.second;
      if (d[u] > d[v] + c) {
        d[u] = d[v] + c;
        b[u] = v;
        q.emplace(d[u], u);
      }
    }
  }
  return d;
}
const int dx[4] = {1, 0, -1, 0};
const int dy[4] = {0, 1, 0, -1};
int main(void) {
  int n;
  string s;
  cin >> n;
  cin >> s;
  int ans = 0;
  for (long long i = 0, i_len = (n); i < i_len; ++i) {
    if (s[i] == '#') {
      ++ans;
    }
  }
  if (ans == s.size()) {
    cout << 0 << endl;
    return 0;
  }
  if (ans == 0) {
    cout << 0 << endl;
    return 0;
  }
  ans = 0;
  vector<int> v(n + 1, 0);
  for (int i = 0; i < n; ++i) {
    if (i + 1 < n && s[i] == '#' && s[i + 1] == '.') ++ans;
  }
  cout << ans << endl;
}
