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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.util.Arrays;
import java.util.Scanner;

/**
 *
 * @author pter9_000
 */
public class Zep2 {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        // TODO code application logic here
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        String str = sc.next();
        boolean arr[]= new boolean[n];
        char zv = '*';
        for(int i=0;i<n;i++){
            if(str.charAt(i)==zv){arr[i]=true;} else {arr[i]=false;}
        }
        int firststar =0;
        while(arr[firststar]==false){
            firststar++;
        }
        //System.out.println("firststar="+firststar);
        //System.out.println(Arrays.toString(arr));
        for(int i=0;i<24;i++){
            int pos = firststar;
            int good = 1;
            while(true){
                pos+=i+1;
                if(pos>n-1){break;}
                if(arr[pos]==true){good++;}
                else
                {break;}
                if(good==5){System.out.println("yes"); return;}
            }
            
        }
        System.out.println("no");
    }
    
}
