#include <bits/stdc++.h>
using namespace std;
template <typename Monoid, typename F>
struct SegmentTree {
  long long sz;
  vector<Monoid> seg;
  const F f;
  const Monoid M1;
  SegmentTree(long long n, const F f, const Monoid &M1) : f(f), M1(M1) {
    sz = 1;
    while (sz < n) sz <<= 1;
    seg.assign(2 * sz, M1);
  }
  void set(long long k, const Monoid &x) { seg[k + sz] = x; }
  void build() {
    for (long long k = sz - 1; k > 0; k--) {
      seg[k] = f(seg[2 * k + 0], seg[2 * k + 1]);
    }
  }
  void update(long long k, const Monoid &x) {
    k += sz;
    seg[k] = x;
    while (k >>= 1) {
      seg[k] = f(seg[2 * k + 0], seg[2 * k + 1]);
    }
  }
  Monoid query(long long a, long long b) {
    Monoid L = M1, R = M1;
    for (a += sz, b += sz; a < b; a >>= 1, b >>= 1) {
      if (a & 1) L = f(L, seg[a++]);
      if (b & 1) R = f(seg[--b], R);
    }
    return f(L, R);
  }
  Monoid operator[](const long long &k) const { return seg[k + sz]; }
  template <typename C>
  long long find_subtree(long long a, const C &check, Monoid &M, bool type) {
    while (a < sz) {
      Monoid nxt = type ? f(seg[2 * a + type], M) : f(M, seg[2 * a + type]);
      if (check(nxt))
        a = 2 * a + type;
      else
        M = nxt, a = 2 * a + 1 - type;
    }
    return a - sz;
  }
  template <typename C>
  long long find_first(long long a, const C &check) {
    Monoid L = M1;
    if (a <= 0) {
      if (check(f(L, seg[1]))) return find_subtree(1, check, L, false);
      return -1;
    }
    long long b = sz;
    for (a += sz, b += sz; a < b; a >>= 1, b >>= 1) {
      if (a & 1) {
        Monoid nxt = f(L, seg[a]);
        if (check(nxt)) return find_subtree(a, check, L, false);
        L = nxt;
        ++a;
      }
    }
    return -1;
  }
  template <typename C>
  long long find_last(long long b, const C &check) {
    Monoid R = M1;
    if (b >= sz) {
      if (check(f(seg[1], R))) return find_subtree(1, check, R, true);
      return -1;
    }
    long long a = sz;
    for (b += sz; a < b; a >>= 1, b >>= 1) {
      if (b & 1) {
        Monoid nxt = f(seg[--b], R);
        if (check(nxt)) return find_subtree(b, check, R, true);
        R = nxt;
      }
    }
    return -1;
  }
};
template <typename Monoid, typename F>
SegmentTree<Monoid, F> get_segment_tree(long long N, const F &f,
                                        const Monoid &M1) {
  return {N, f, M1};
}
void solve() {
  long long N;
  cin >> N;
  string S;
  cin >> S;
  auto seg = get_segment_tree(
      N, [](long long a, long long b) { return a + b; }, 0);
  for (long long i = (0), i_len = (N); i < i_len; ++i) {
    if (S[i] == '#') {
      seg.set(i, 1);
    }
  }
  seg.build();
  long long ans = 1e15;
  for (long long i = (0), i_len = (N); i < i_len; ++i) {
    long long left = seg.query(0, i + 1);
    long long right = seg.query(i + 1, N + 1);
    ans = min(ans, left + (N - i) - right);
  }
  cout << ans << endl;
}
signed main() {
  cin.tie(nullptr)->sync_with_stdio(false);
  solve();
}
