
// Problem : C - Stones
// Contest : AtCoder - Tenka1 Programmer Beginner Contest 2019
// URL : https://atcoder.jp/contests/tenka1-2019-beginner/tasks/tenka1_2019_c
// Memory Limit : 1024 MB
// Time Limit : 2000 ms
// Powered by CP Editor (https://github.com/cpeditor/cpeditor)
/*⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⣠⣶⡾⠏⠉⠙⠳⢦⡀⠀⠀⠀
⠀⠀⠀⣴⠿⠏⠀⠀⠀⠀⠀⠀⢳⡀⠀
⠀⠀⢠⣟⣋⡀⢀⣀⣀⡀⠀⣀⡀⣧⠀
⠀⠀⢸⣯⡭⠁⠸⣛⣟⠆⡴⣻⡲⣿⠀
⠀⠀⣟⣿⡭⠀⠀⠀⠀⠀⢱⠀⠀⣿⠀
⠀⠀⠙⢿⣯⠄⠀⠀⠀⢀⡀⠀⠀⡿⠀⠀
⠀⠀⠀⠀⠹⣶⠆⠀⠀⠀⠀⠀⡴⠃⠀⠀
⠀⠀⠀⠀⠀⢸⣷⡦⢤⡤⢤⣞⣁⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
⠀⠀⢀⣤⣴⣿⣏⠁⠀⠀⠸⣏⢯⣷⣖⣦⡀⠀⠀⠀⠀⠀⠀
⢀⣾⣽⣿⣿⣿⣿⠛⢲⣶⣾⢉⡷⣿⣿⠵⣿⠀⠀⠀⠀⠀⠀
⣼⣿⠍⠉⣿⡭⠉⠙⢺⣇⣼⡏⠀⠀⠀⣄⢸⠀⠀⠀⠀⠀⠀
⣿⣿⣧⣀⣿.........⣀⣰⣏⣘⣆⣀⠀
*/
#include <bits/stdc++.h> 
#pragma GCC optimize ("O3")
#pragma GCC target ("sse4")
 
#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
 
 
using namespace std;
using namespace __gnu_pbds;
 
typedef long long ll;
typedef long double ld;
typedef complex<ld> cd;
 
typedef pair<int, int> pi;
typedef pair<ll,ll> pl;
typedef pair<ld,ld> pd;
 
typedef vector<int> vi;
typedef vector<ld> vd;
typedef vector<ll> vl;
typedef vector<pi> vpi;
typedef vector<pl> vpl;
typedef vector<cd> vcd;
 
#define l00p(i, a, b) for (int i=a; i<(b); i++)
#define loop(i, a) for (int i=0; i<(a); i++)
#define rep1(i,a,b) for (int i = (b)-1; i >= a; i--)
#define rep(i,a) for (int i = (a)-1; i >= 0; i--)
#define trav(a,x) for (auto& a : x)
#define uid(a, b) uniform_int_distribution<int>(a, b)(rng)

#define sz(x) (int)(x).size()
#define mp make_pair
#define pb push_back
#define f first
#define s second
#define lb lower_bound
#define ub upper_bound
#define all(x) x.begin(), x.end()
#define ins insert
#define imax INT_MAX
#define imin INT_MIN
//#define MOD 998244353
 
template<class T> bool ckmin(T& a, const T& b) { return b < a ? a = b, 1 : 0; }
template<class T> bool ckmax(T& a, const T& b) { return a < b ? a = b, 1 : 0; }

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

const ld pii=3.14159265359; 
const int MOD = 1000000007;
const char nl = '\n';
const ll INF = 1e18;
const int MX = 100001; //check the limits, dummy

int main() {
	 
	ios_base::sync_with_stdio(0); cin.tie(0); 
	int n;
	cin>>n;
	string s;
	cin>>s;
	vi pref1(n),pref2(n);
	int j=0;
	loop(i,n)
	{
		if(s[i]=='#')
		j++;
		pref1[i]=j;
	}
	j=0;
	rep(i,n)
	{
		if(s[i]=='.')
		j++;
		pref2[i]=j;
	}
	int mn=imax;
	loop(i,n-1)
	{
		mn=min(pref2[0],pref1[n-1]);
		mn=min(mn,pref2[i+1]+pref1[i]);
	}
	cout<<mn;
	return 0;
}
// read the question correctly (ll vs int)
// template by bqi343