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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 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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 57
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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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 42
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 10
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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
.*.......................*...............................................*.......................*.
 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
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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

num_segments = 0
for line in sys.stdin:
    if num_segments == 0:
        num_segments = int(line.rstrip())
    else:
        segments = map((lambda x: 1 if x == '*' else 0), list(line.rstrip()))
        start = -1
        verdict = "no"
        for a in range(len(segments)):
            if segments[a] == 1:
                if start == -1:
                    start = a
                else:
                    distance = a - start
                    first = a + distance
                    second = first + distance
                    third = second + distance
                    if len(segments) > third and segments[first] and segments[second] and segments[third]:
                        verdict = "yes"
                        break
        print verdict
