#include <iostream>
#include <sstream>
#include <fstream>
#include <string>
#include <vector>
#include <deque>
#include <queue>
#include <stack>
#include <set>
#include <cstring>
#include <cassert>
#include <list>
#include <map>
#include <unordered_map>
#include <iomanip>
#include <algorithm>
#include <functional>
#include <utility>
#include <bitset>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <cstdio>
#include <limits>
using namespace std;
typedef long long          ll;
typedef unsigned long long ull;
typedef long double        ld;
typedef pair<int,int>      pii;
typedef pair<ll,ll>        pll;
typedef vector<int>        vi;
typedef vector<long long>  vll;
#define left(x)		   (x << 1)
#define right(x) 	   (x << 1) + 1
#define mid(l, r) 	   ((l + r) >> 1)
#define mp                 make_pair
#define pb                 push_back
#define all(a)             a.begin(),a.end()
#define debug(x)	   {cerr <<#x<<" = " <<x<<"\n"; }
#define debug2(x, y)       {cerr <<#x<<" = " <<x<<", "<<#y <<" = " <<y <<"\n";}
#define debug3(x, y, z)    {cerr <<#x<<" = " <<x<<", "<<#y <<" = " <<y <<", "<<#z<<" = "<<z<<"\n";}
#define debug4(x, y, z, w) {cerr <<#x<<" = " <<x<<", "<<#y <<" = " <<y <<", "<<#z<<" = "<<z<<", "<<#w << " = " <<w <<"\n";}
#define ss                 second
#define ff                 first
#define m0(x) 		   memset(x,0,sizeof(x))

template<typename T >T min_ ( T a , T b ) { return a > b ? b : a ; }
template < typename T ,  typename... Ts > T min_( T first , Ts... last ){ return  min_(first, min_(last...)); }
template<typename T >T max_ ( T a , T b ) { return a > b ? a : b ; }
template < typename T ,  typename... Ts > T max_( T first , Ts... last ){ return  max_(first, min_(last...)); }

template<class T, class S> std::ostream& operator<<(std::ostream &os, const std::pair<T, S> &t) {
	os<<"("<<t.first<<", "<<t.second<<")";
	return os;
}
template<typename T> ostream& operator<< (ostream& out, const vector<T>& v) {
    out << "["; size_t last = v.size() - 1; for(size_t i = 0; i < v.size(); ++i) {
    out << v[i]; if (i != last) out << ", "; } out << "]"; return out;
}

ll pwr(ll base, ll p, ll mod){
ll ans = 1; while(p) { if(p&1) ans=(ans*base)%mod; base=(base*base)%mod; p/=2; } return ans;
}
ll gcd(ll a, ll b) {  return b == 0 ? a : gcd(b,a%b); }
ll lcm(ll a, ll b) {  return a*(b/gcd(a,b)); }

const long double PI = (long double)(3.1415926535897932384626433832795);
const ll  mx_ll   = numeric_limits<ll> :: max();
const int mx_int  = numeric_limits<int> :: max();
const int mod = 1e9+7;

const int maxn = 3e5+7;
int dp[maxn][2]; 
// 0 - . 
// 1 - #
int main()
{
    ios_base::sync_with_stdio(false); cin.tie(0);
#ifdef __APPLE__
    freopen("test.in", "rb", stdin);
    //freopen("  .out", "wb", stdout);
#endif
    int n; cin >> n;
    string str; cin >> str;
    int fans = 0;

    dp[0][0] = (str[0] == '.' ? 0 : 1);
    dp[0][1] = (str[0] == '.' ? 1 : 0);

    for(int i = 1; i < n; i++)
    {
        if(str[i] == '.') // 0
        {
            dp[i][0] = dp[i-1][0];
            dp[i][1] = 1 + min(dp[i-1][0],dp[i-1][1]);
        }
        else // 1
        {
            dp[i][0] = 1 + dp[i-1][0];
            dp[i][1] = min(dp[i-1][0],dp[i-1][1]);
        }
        //debug2(dp[i][0],dp[i][1]);
    }
    
    cout << min(dp[n-1][0],dp[n-1][1]) << "\n";

    return 0;
}



Measured memory_bytes: 2196