Nested quotations are great not only for writing literature with a complex narrative structure, but also in programming languages. While it may seem necessary to use different quotation marks at different nesting levels for clarity, there is an alternative. We can display various nesting levels using $k$-quotations, which are defined as follows.

<p>A $1$-quotation is a
string that begins with a quote character, ends with another
quote character and contains no quote characters in-between.
These are just the usual (unnested) quotations. For example,
<tt class="ttfamily">'this is a string'</tt> is a 
$1$-quotation.</p>

<p>For $k &gt; 1$, a
$k$-quotation is a string
that begins with $k$ quote
characters, ends with another 
$k$ quote characters and contains a
nested string in-between. The nested string is a non-empty
sequence of <span style="width:" class="mbox">
$(k-1)$-quotations, which may
be preceded, separated, and/or succeeded by any number of
non-quote characters. For example, <tt class="ttfamily">''All
'work' and no 'play'''</tt> is a 
$2$-quotation.</span></p>

<p>Given a description of a string, you must determine its
maximum possible nesting level.</p>

<h3>Input</h3>
<p>
Multiple test cases. Please process until EOF is reached. For each test case:</p>
<p>The input consists of two lines. The first line contains an
integer $n$ (
$1 \le n \le 100$). The second line
contains $n$ integers
$a_1, a_2, \ldots , a_ n$
($1 \le a_ i \le 100$),
which describe a string as follows. The string starts with
$a_1$ quote characters,
which are followed by a positive number of non-quote
characters, which are followed by 
$a_2$ quote characters, which are
followed by a positive number of non-quote characters, and so
on, until the string ends with 
$a_ n$ quote characters.</p>

<h3>Output</h3>

<p>For each test case, display the largest number 
$k$ such that a string described by
the input is a 
$k$-quotation. If there is no such
$k$, display <tt class="tt">no quotation</tt> instead.</p>

Example

Input:
5
2 1 1 1 3
1
22
1
1
Output:
2
4
no quotation