20
.*..*...*....*.....*
 97
****.***.***.*..**.**.*.*.***.*............*..*......*.***.**.*.***.*.***.*..*.**.*.***.**.*****.
 5
*.***
 4
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 11
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 72
.***.**.*.*...*****.*.*.*.*.**....**.*.**..*.*...**..***.**.**..*.**..**
 89
..**..**..*.********....*.*****.**.****...*......*******..*.**.*****..*..****....*...**..
 6
***.**
 54
...***.*...****.*..****....*..**..**..***.*..**...**..
 100
****************************************************************************************************
 53
*.*.****.*.*......**....**.***.*.*.**.*.*.***...*..*.
 87
*..*..***.**.*...****...*....***....***......*..*.*.*****.**..*.***...*.****..**.*..***
 90
**....****.***..***.*.*****...*.*.***..***.******.**...***..*...*****..*.**.**...*..**...*
 55
...*..*.*.**..*.*....*.****..****....*..***.*****..*..*
 21
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 41
*******....*..*.**..***.*...****.***.*...
 31
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 64
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 10
*****....*
 99
**...*.*.*..*....**.***..*...***..***.**.*.....*.*....*...*.**.**.****..**..*.*..*.***....**...**.*
 69
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 99
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 98
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 57
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 64
***.*...*...*.***.....*.....**.*****.*.*...*..*.*..***..*...***.
 17
*...*...*...*...*
 100
*...............................................................................................****
 11
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 1
.
 100
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 56
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 99
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 10
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 51
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 17
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 97
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 42
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 5
*****
 42
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 71
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 99
.*..**..*..*..**...***.****.*...*....*****.....**..****.*..*....****..**..*****..*....**.*.**..**..
 42
.*.*...*..**.****...****..*.*.***....**...
 10
.*.*.*.*..
 1
*
 5
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 16
*.**.**.**.*..*.
 100
*.......................*.......................*.......................*.......................*...
 7
***.***
 58
**.*.*.**..******.**.*..*.**.*.*******.**.*.**.*..*****.*.
 67
..**.*...*.....****.***.**.*....***..***.*..***.....*******.....*.*
 99
.*.......................*...............................................*.......................*.
 6
......
 11
.**.*..*.**
 15
..........*****
 75
..*.**..*.*****.......*....*.*.*..**.*.***.*.***....******.****.*.....****.
 45
.***..******....***..**..*.*.*.**..**..*.**..
 13
*..*..*..*..*
 5
**.**
 100
*****...............................................................................................
 99
..*.*..**.*.*.******.*.*.**.**.**.*..**.*.*****..*.*.****.*....**....*****.....***..**....***.*.*.*
 99
***************************************************************************************************
 5
****.

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
n = int(input())
mj = 0
cj = 0
path = input()
i = 0
while path[i] != "*":
	i = i + 1
	if i == len(path) - 1:
		i = 0
		break
for c in range(i, len(path)):
	if path[c] == ".":
		cj = cj + 1
		if cj > mj:
			mj = cj
	else:
		cj = 0


answ = 'no'

buf = i
mj = mj + 1
while answ == 'no' and mj < len(path):
	i = buf
	while i < len(path) and path[i] != ".":
		m = 0
		for k in range(i, len(path), mj):
			if path[k] == "*":
				m = m + 1
			elif m < 5:
				m = 0
		if m > 4:
			answ = 'yes'
		i = i + 1
	if answ == 'no':
		mj = mj + 1
print(answ)