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****.

no yes no no no yes yes no yes yes yes yes yes yes no yes yes yes yes yes yes yes yes yes yes yes no no no yes yes yes yes no no yes yes yes yes yes no yes yes no no no yes yes no yes yes no no no yes yes yes yes no yes yes yes no
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

/**
 *
 * @author Donato
 */
public class KingOfThieves {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) throws IOException {
         BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
         int n=Integer.parseInt(br.readLine());
         String nivel=br.readLine();
         int salto=0;
         int saltos=0;
        
         int i=0;
         int h=i;
         int j=1;
         while(nivel.charAt(i)=='.'&& i<n){
             i++;
         }
         j=i+1;
         while(i<n&&saltos<4){
             if(j>n-1){
                 i++;
                 h=i;
                 j=i+1;
                 salto=0;
                 saltos=0;
             }
             else{
                while(j<n&&nivel.charAt(j)=='.'){
                    j++;
                }
                if(salto==j-h &&j<n){
                    saltos++;
                    
                }
                else{
                    j=j+1;
                    saltos=0;
                }
                h=j;
             }
             
         }
         if(saltos>=4){
             System.out.println("yes");
         }
         else{
             System.out.println("no");
         }
    }
    
}