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

p2 = p1 + 1 if p1 > 0 else p2

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
    plats = 0
    for j in xrange(i, n, step):
      #if step == 15 and i == 6:
      #  print "j", j
      if ds[j] == '.':
        fall = True
        break
      plats += 1

    if not fall:
      v = (n - i)/step + 1
      #print plats, v
      if plats == v:
        res = 'yes'
        break
  if res == 'yes':
    break

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

print res
sys.exit(0)
