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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
#!/usr/bin/python
import re
import inspect
from sys import argv, exit

def rstr():
    return input()

def rint():
    return int(input())

def rints(splitchar=' '):
    return [int(i) for i in input().split(splitchar)]

def varnames(obj, namespace=globals()):
    return [name for name in namespace if namespace[name] is obj]

def pvar(var, override=False):
    prnt(varnames(var), var)

def prnt(*args, override=False):
    if '-v' in argv or override:
        print(*args)

if __name__ == '__main__':
    n = rint()
    s = rstr()
    course = [1 if c=='*' else 0 for c in s]
    prnt(course)
    for i,c in enumerate(course):
        if not c:
            prnt(c)
            continue
        else:
            prnt('Using c=',i)
            for j in range(1, len(course)):
                if i+j*4 >= len(course):
                    break
                if course[i+j] and course[i+j*2] and course[i+j*3] and course[i+j*4]:
                    print('yes')
                    exit(0)

    print('no')
