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

"""
"""
n = input()
ds = list(raw_input())

start = time.clock()

quoter = n / 4

p1 = -1
p2 = n
for i in xrange(n):
  if p1 == -1 and ds[i] == '*':
    p1 = i
    continue
  if p1 >= 0 and ds[i] == '.':
    p2 = i
    break

max_split = int(n/2)

res = 'no'
#print "n/2", max_split
#print "p1: %d, p2: %d" % (p1, p2)
for step in xrange(2, max_split+1):
  for i in xrange(p1, p2):
    #print "step: %d, i: %d" % (step, i)
    fall = False
    for j in xrange(i, n, step):
      if ds[j] == '.':
        fall = True
        break
    if not fall:
      res = 'yes'
      break
  if res == 'yes':
    break

end = time.clock()
#print end - start

print res
sys.exit(0)
