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 97
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 72
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 21
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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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 56
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 42
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 71
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 42
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 100
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 67
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 6
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 13
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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
n = input()
s = raw_input()
arr = []
i = 0
while i<len(s):
    if s[i]=='*':
        arr.append(i+1)
    i+=1
i = 0
ansy = []
tog = 1
while i<len(arr):
    j = i+1
    while j<len(arr):
        d = arr[j]-arr[i]
        q = [arr[i],arr[j]]
        k = j+1
        while k<len(arr):
            if d==arr[k]-q[-1]:
                q.append(arr[k])
            k+=1
            if len(q)>=5:
                print 'yes'
                tog = 0
                break
        ansy.append(q)
        if not tog:
            break
        
        j+=1
    if not tog:
        break
    i+=1
if tog:
    print 'no'