A. King of Thieves

import java.util.Scanner;

public class A526 {

public static void solve(){
Scanner in=new Scanner(System.in);
int n=in.nextInt();
char [] s = in.next().toCharArray();
for(int i=1;i<=n/4;++i){
for(int j=0;j+4*i<n;++j){
if(s[j]=='*'&&s[j+i]=='*'&&s[j+2*i]=='*'&&s[j+3*i]=='*'&&s[j+4*i]=='*'){
System.out.println("yes");
return ;
}//if
}//for
}//for
System.out.println("no");
return;
}
public static void main(String [] args){
new A526().solve();
}
}