20
.*..*...*....*.....*
 97
****.***.***.*..**.**.*.*.***.*............*..*......*.***.**.*.***.*.***.*..*.**.*.***.**.*****.
 5
*.***
 4
****
 11
.*.*.*.*...
 72
.***.**.*.*...*****.*.*.*.*.**....**.*.**..*.*...**..***.**.**..*.**..**
 89
..**..**..*.********....*.*****.**.****...*......*******..*.**.*****..*..****....*...**..
 6
***.**
 54
...***.*...****.*..****....*..**..**..***.*..**...**..
 100
****************************************************************************************************
 53
*.*.****.*.*......**....**.***.*.*.**.*.*.***...*..*.
 87
*..*..***.**.*...****...*....***....***......*..*.*.*****.**..*.***...*.****..**.*..***
 90
**....****.***..***.*.*****...*.*.***..***.******.**...***..*...*****..*.**.**...*..**...*
 55
...*..*.*.**..*.*....*.****..****....*..***.*****..*..*
 21
*.*...*.*...*.*...*.*
 41
*******....*..*.**..***.*...****.***.*...
 31
.******.**.**....*.*********...
 64
*.***...**...*..*...*....*..***.*.*.*.***.*.**...**.*.*.*..*....
 10
*****....*
 99
**...*.*.*..*....**.***..*...***..***.**.*.....*.*....*...*.**.**.****..**..*.*..*.***....**...**.*
 69
.***...*.***.**...*....*.***.*..*....**.*...**....*.*..**....**..*.**
 99
.*.......................*.......................*.......................*.......................*.
 98
.**..**.*****..***...*.**..*..*....*******..**....*.****.**.*.....*.**..***.**..***.*******..****.
 57
**...*....**.**.*.******.**..**.*.....**.***..***...**..*
 64
***.*...*...*.***.....*.....**.*****.*.*...*..*.*..***..*...***.
 17
*...*...*...*...*
 100
*...............................................................................................****
 11
*...**..*.*
 1
.
 100
*.....................*.....................*.....................*.....................*...........
 56
**.*..*...***.*.**.**..**.*.*.*.**...*.**.**....*...**..
 99
***....*.....****.*.**.*.*.**.*.*.*..*...*..*...***..*.*...*.*...***.*.*...**.**.*******....**....*
 10
.*.*.*.*.*
 51
....****....*........*.*..**........*....****....*.
 17
.*..*..*.....*..*
 97
...*..*...*******.*.**..**..******.*.*..*****.*...***.*.**.**.**..**.******.****.*.***.**..*...**
 42
***.*..*.*.***...**..*..**....**..*..*...*
 5
*****
 42
..*...*.*..**..*.*.*..**...**.***.*.******
 71
**.**..*****.*.*.*.********.....*****.****.*..***...*.*.*.**.****.**.**
 5
.****
 99
.*..**..*..*..**...***.****.*...*....*****.....**..****.*..*....****..**..*****..*....**.*.**..**..
 42
.*.*...*..**.****...****..*.*.***....**...
 10
.*.*.*.*..
 1
*
 5
***.*
 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
import sys

n = int(sys.stdin.readline())
puzzle = sys.stdin.readline().rstrip()

startIndex = -1
canMakeIt_p = False

# get start index
for ii in xrange(0, len(list(puzzle))):
	if (list(puzzle)[ii] == '*'):
		startIndex = ii
		break

for si in xrange(0, len(list(puzzle))):
	if (puzzle[si] == '.'):
		continue
	else:
		startIndex = si
	for ii in xrange(1, len(list(puzzle))):
		if (canMakeIt_p):
			break
		jumpCount = 0
		for jj in xrange(startIndex, len(list(puzzle)), ii):
			if (puzzle[jj] == '.'):
				break

			if (jumpCount == 3):
				canMakeIt_p = True
				break

			jumpCount = jumpCount + 1

if (canMakeIt_p):
	print "yes"
else:
	print "no"