#include <bits/stdc++.h>
using namespace std;
inline long long modpow(long long x, long long y,
                        long long m = (long long)((1e9) + 7)) {
  long long res = 1;
  while (y) {
    if (y % 2) {
      res *= x;
      res %= m;
    }
    x = x * x % m;
    y /= 2;
  }
  return res;
}
long long mypow(long long x, long long y) {
  long long res = 1;
  while (y) {
    if (y % 2) {
      res *= x;
    }
    x = x * x;
    y /= 2;
  }
  return res;
}
bool prime(long long x) {
  for (long long i = 2; i * i <= x; i++) {
    if (!(x % i)) {
      return false;
    }
  }
  return true;
}
inline long long gcd(long long x, long long y) {
  if (!y) {
    return x;
  }
  return gcd(y, x % y);
}
long long keta(long long x) {
  long long ans = 0;
  while (x) {
    x /= 10;
    ans++;
  }
  return ans;
}
long long ketasum(long long x) {
  long long ans = 0;
  while (x) {
    ans += x % 10;
    x /= 10;
  }
  return ans;
}
inline long long lcm(long long x, long long y) {
  long long ans = x / gcd(x, y) * y;
  return ans;
}
long long twobeki(long long x) {
  long long ans = 0;
  while (1) {
    if (!(x & 1)) {
      ans++;
      x /= 2;
    } else {
      break;
    }
  }
  return ans;
}
template <class T, class U>
inline bool chmax(T& lhs, const U& rhs) {
  if (lhs < rhs) {
    lhs = rhs;
    return 1;
  }
  return 0;
}
template <class T, class U>
inline bool chmin(T& lhs, const U& rhs) {
  if (lhs > rhs) {
    lhs = rhs;
    return 1;
  }
  return 0;
}
void Yes() { cout << "Yes" << endl; }
void No() { cout << "No" << endl; }
void YES() { cout << "YES" << endl; }
void NO() { cout << "NO" << endl; }
long long kai(long long x, long long y) {
  long long res = 1;
  for (long long i = x - y + 1; i <= x; i++) {
    res *= i;
    res %= (long long)((1e9) + 7);
  }
  return res;
}
long long comb(long long x, long long y) {
  if (y > x) return 0;
  return kai(x, y) * modpow(kai(y, y), (long long)((1e9) + 7) - 2) %
         (long long)((1e9) + 7);
}
template <class T>
class SegTree {
  long long n;
  vector<T> data;
  T def;
  function<T(T, T)> operation;
  function<T(T, T)> update;
  T _query(long long a, long long b, long long k, long long l, long long r) {
    if (r <= a || b <= l) return def;
    if (a <= l && r <= b)
      return data[k];
    else {
      T c1 = _query(a, b, 2 * k + 1, l, (l + r) / 2);
      T c2 = _query(a, b, 2 * k + 2, (l + r) / 2, r);
      return operation(c1, c2);
    }
  }

 public:
  SegTree(size_t _n, T _def, function<T(T, T)> _operation,
          function<T(T, T)> _update)
      : def(_def), operation(_operation), update(_update) {
    n = 1;
    while (n < _n) {
      n *= 2;
    }
    data = vector<T>(2 * n - 1, def);
  }
  void change(long long i, T x) {
    i += n - 1;
    data[i] = update(data[i], x);
    while (i > 0) {
      i = (i - 1) / 2;
      data[i] = operation(data[i * 2 + 1], data[i * 2 + 2]);
    }
  }
  T query(long long a, long long b) { return _query(a, b, 0, 0, n); }
  T operator[](long long i) { return data[i + n - 1]; }
};
class Union_Find {
  vector<long long> par;
  vector<long long> rankmy;
  vector<long long> ookisa;

 public:
  Union_Find(long long size) {
    par = vector<long long>(size);
    rankmy = vector<long long>(size);
    ookisa = vector<long long>(size);
    for (long long i = 0; i < size; i++) {
      par[i] = i;
      ookisa[i] = 1;
    }
  }
  long long find(long long x) {
    if (par[x] == x) {
      return x;
    }
    return par[x] = find(par[x]);
  }
  void unite(long long x, long long y) {
    x = find(x);
    y = find(y);
    if (x == y) {
      return;
    }
    if (rankmy[x] < rankmy[y]) {
      par[x] = y;
      ookisa[y] += ookisa[x];
      ookisa[x] = 0;
    } else {
      par[y] = x;
      ookisa[x] += ookisa[y];
      ookisa[y] = 0;
      if (rankmy[x] == rankmy[y]) {
        rankmy[x]++;
      }
    }
  }
  long long size(long long i) {
    i = find(i);
    return ookisa[i];
  }
  bool same(long long x, long long y) { return find(x) == find(y); }
};
long long perm[1000005];
void init_perm() {
  perm[0] = 1;
  for (long long i = 1; i <= 1000000; i++) {
    perm[i] = perm[i - 1] * i % (long long)((1e9) + 7);
  }
}
long long nCk(long long x, long long y) {
  return perm[x] * modpow(perm[x - y], (long long)((1e9) + 7) - 2) %
         (long long)((1e9) + 7) * modpow(perm[y], (long long)((1e9) + 7) - 2) %
         (long long)((1e9) + 7);
}
double kyori(pair<long long, long long> f, pair<long long, long long> s) {
  double ans = 0;
  double t = fabs(f.first - s.first);
  double y = fabs(f.second - s.second);
  ans = sqrt(t * t + y * y);
  return ans;
}
inline string stringmax(string& x, string& y) {
  if (x.size() > y.size()) {
    return x;
  }
  if (x.size() < y.size()) {
    return y;
  }
  for (long long i = 0; i < x.size(); i++) {
    if (x[i] > y[i]) {
      return x;
    }
    if (x[i] < y[i]) {
      return y;
    }
  }
  return x;
}
long long n, a, b, ans, p;
bool now = 0;
string s;
signed main() {
  ios::sync_with_stdio(false);
  std::cin.tie(nullptr);
  cin >> n >> s;
  for (long long i = 0; i < n; i++) {
    if (s[i] == '#') {
      ans++;
    }
  }
  for (long long i = 0; i < n; i++) {
    if (s[i] == '#') {
      now = 1;
    }
    if (now) {
      if (s[i] == '.') {
        p++;
      }
    }
  }
  cout << min(p, ans) << "\n";
}
