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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
class CodeforcesTask526ASolution:
    def __init__(self):
        self.result = ''
        self.n = 0
        self.level = ''

    def read_input(self):
        self.n = int(input())
        self.level = input()

    def process_task(self):
        can = False
        for y in range(1, self.n):
            for x in range(self.n - y - 1):
                do = True
                for z in range(5):
                    if x + z * y >= self.n:
                        do = False
                        break
                    if self.level[x + z * y] != "*":
                        do = False
                        break
                if do:
                    can = do
                    break
            if can:
                break
        self.result = "yes" if can else "no"

    def get_result(self):
        return self.result


if __name__ == "__main__":
    Solution = CodeforcesTask526ASolution()
    Solution.read_input()
    Solution.process_task()
    print(Solution.get_result())
