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.*..*...*....*.....*
 97
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 5
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 72
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 89
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 100
****************************************************************************************************
 53
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 87
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 21
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 31
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 64
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 57
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 17
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 100
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 11
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 56
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 99
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 42
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 71
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 42
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 67
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 75
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 45
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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=int(input())
d=list(input())
dun = list()
ok =False
initial = 0
for i in range(len(d)):
    if d[i]=='.':
        dun.append(False)
    else :
        dun.append(True)
        if ok == False:
            initial = i
            ok = True
ok = False
if (n-initial)//4 == 0:
    print('no')
else :
    while initial+1<len(dun) and not ok:
        for i in range(1, (n-initial)//4+1):
            nok = False
            count=0
            for j in range(initial,n,i):
                if dun[j]== False:
                    nok=True
                    break
                else :
                    count += 1
                if count == 5:
                    break
            if nok==False and count ==5:
                ok=True
                break
        if not ok :
            initial += 1
            while initial+1>len(dun) and dun[initial]==False:
                initial += 1
        else :
            break
    if not ok:
        print('no')
    else :
        print('yes')