/**
 * author: said_v15
**/

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>

using namespace std;
using namespace __gnu_pbds;
typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> oset;

typedef long long  ll;

#define fast ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0)
#define forn for(int i=0;i<n;i++) 
#define pb push_back 
#define sc second 
#define f first 
#define kek cout<<"\n";
#define fla cout<<endl;
#define rep(i,a,b) for(int i=a;i<b;i++)
#define all(v) ((v).begin()), ((v).end()) 
#define int ll


const ll MOD = (ll) 1e9 + 7;
const ll MOD1 = 998244353;
const int MAXN = 100010;
const int INF = 1e9;
const ll LL_INF=1e18;
const double pi=3.1415926535;

int divide(int a, int b)
{
          return (a+b-1)/b;
}

int32_t main()
{
    #if defined(_DEBUG)
	freopen("input.txt", "r", stdin);
	freopen("output.txt", "w", stdout);
    #endif
 fast;
 // cout << fixed << setprecision(12) << ans;
 // string al = "abcdefghijklmnopqrstuvwxyz";
 
 int questions=1;
 // cin>>questions;
 while(questions--)
 {
          int n,k;
          cin>>n>>k;
          string s;
          cin>>s;
          if(n==1) 
          {
                    cout<<s;
                    return 0;
          }
          set<int> se;
          for(int i=0;i<n;i++) 
          {
                    if(s[i]=='.') continue;
                    if(!i) 
                    {
                              if(s[i+1]=='.') se.insert(i+1);
                    }
                    else if(i==n-1) 
                    {
                              if(s[i-1]=='.') se.insert(i-1);
                    }
                    else 
                    {
                              if(s[i-1]=='.') se.insert(i-1);
                              if(s[i+1]=='.') se.insert(i+1);
                    }
          }
          vector<int> del;
          vector<int> add;
          while(k--) 
          {
                    del.clear();
                    add.clear();
                    if(!se.size()) break;
                    for(auto &x: se) 
                    {
                              int pos=x;
                              if(pos==0 || pos==n-1) 
                              {
                                        s[pos]='*';
                                        del.pb(pos);
                                        continue;
                              }
                              del.pb(pos);
                              s[pos]='*';
                              if(s[pos+1]=='.') add.pb(pos+1);
                              if(s[pos-1]=='.') add.pb(pos-1);
                    }
                    for(auto &x: del) se.erase(x);
                    for(auto &x: add) se.insert(x);
          }
          cout<<s;
           
 }

    
 
 // !!! LOOK AT NUMBER OF QUESTIONS IN A PROBLEM !!! (cin>>questions)
 

  // cout <<"Runtime is: "<<clock() * 1.0 / CLOCKS_PER_SEC <<endl;
   return 0;
   
}

import java.io.*;
import java.util.ArrayList;
import java.util.StringTokenizer;

public class codeforcesSIT_H {
    private static void solve(FastIOAdapter ioAdapter) {
        int n = ioAdapter.nextInt();
        int k = ioAdapter.nextInt();

        char[] a = ioAdapter.next().toCharArray();
        int start = -1;
        int end = -1;
        ArrayList<int[]> list = new ArrayList<>();
        for (int i = 0; i < n; i++) {
            if (a[i] == '*') {
                if (i == 0 || a[i - 1] == '.') {
                    start = i;
                }
                if (i == n - 1 || a[i + 1] == '.') {
                    end = i;
                    list.add(new int[]{Math.max(0, start - k), Math.min(n - 1, end + k)});
                }
            }
        }

        if (!list.isEmpty()) {
            ArrayList<int[]> res = new ArrayList<>();
            res.add(list.get(0));
            for (int i = 1; i < list.size(); i++) {
                if (list.get(i)[0] - 1 <= res.get(res.size() - 1)[1]) {
                    res.get(res.size() - 1)[1] = list.get(i)[1];
                } else {
                    res.add(list.get(i));
                }
            }

            for (int[] re : res) {
                for (int i = re[0]; i <= re[1]; i++) {
                    a[i] = '*';
                }
            }
        }

        for (int i = 0; i < a.length; i++) {
            ioAdapter.out.print(a[i]);
        }
        ioAdapter.out.println();
    }


    public static void main(String[] args) throws Exception {
        try (FastIOAdapter ioAdapter = new FastIOAdapter()) {
            int count = 1;
            //count = ioAdapter.nextInt();
            while (count-- > 0) {
                solve(ioAdapter);
            }
        }
    }

    static class FastIOAdapter implements AutoCloseable {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        public PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter((System.out))));
        StringTokenizer st = new StringTokenizer("");

        String next() {
            while (!st.hasMoreTokens())
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            return st.nextToken();
        }

        int nextInt() {
            return Integer.parseInt(next());
        }

        int[] readArray(int n) {
            int[] a = new int[n];
            for (int i = 0; i < n; i++) a[i] = nextInt();
            return a;
        }

        long nextLong() {
            return Long.parseLong(next());
        }

        @Override
        public void close() throws Exception {
            out.flush();
            out.close();
            br.close();
        }
    }
}

https://pastebin.com/ZXu2pAPr

https://pastebin.com/BBt35kCZ