Let's define a string &lt;x&gt; as an opening tag, where *x* is any small letter of the Latin alphabet. Each opening tag matches a closing tag of the type &lt;/x&gt;, where *x* is the same letter.

Tegs can be nested into each other: in this case one opening and closing tag pair is located inside another pair.

Let's define the notion of a XML-text: 
 -  an empty string is a XML-text -  if *s* is a XML-text, then *s*'=&lt;a&gt;+*s*+&lt;/a&gt; also is a XML-text, where *a* is any small Latin letter -  if *s*<sub class="lower-index">1</sub>, *s*<sub class="lower-index">2</sub> are XML-texts, then *s*<sub class="lower-index">1</sub>+*s*<sub class="lower-index">2</sub> also is a XML-text 
You are given a XML-text (it is guaranteed that the text is valid), your task is to print in the following form: 
 -  each tag (opening and closing) is located on a single line -  print before the tag 2 * *h* spaces, where *h* is the level of the tag's nestedness.
The input data consists on the only non-empty string — the XML-text, its length does not exceed 1000 characters. It is guaranteed that the text is valid. The text contains no spaces.
<a><b><c></c></b></a>
<a>
  <b>
    <c>
    </c>
  </b>
</a>
<a><b></b><d><c></c></d></a>
<a>
  <b>
  </b>
  <d>
    <c>
    </c>
  </d>
</a>
<z></z>
<z>
</z>
<u><d></d></u><j></j>
<u>
  <d>
  </d>
</u>
<j>
</j>
<a></a><n></n><v><r></r></v><z></z>
<a>
</a>
<n>
</n>
<v>
  <r>
  </r>
</v>
<z>
</z>
<c><l></l><b><w><f><t><m></m></t></f><w></w></w></b></c>
<c>
  <l>
  </l>
  <b>
    <w>
      <f>
        <t>
          <m>
          </m>
        </t>
      </f>
      <w>
      </w>
    </w>
  </b>
</c>
<u><d><g><k><m><a><u><j><d></d></j></u></a></m><m></m></k></g></d></u>
<u>
  <d>
    <g>
      <k>
        <m>
          <a>
            <u>
              <j>
                <d>
                </d>
              </j>
            </u>
          </a>
        </m>
        <m>
        </m>
      </k>
    </g>
  </d>
</u>
<x><a><l></l></a><g><v></v><d></d></g><z></z><y></y></x><q><h></h><s></s></q><c></c><w></w><q></q>
<x>
  <a>
    <l>
    </l>
  </a>
  <g>
    <v>
    </v>
    <d>
    </d>
  </g>
  <z>
  </z>
  <y>
  </y>
</x>
<q>
  <h>
  </h>
  <s>
  </s>
</q>
<c>
</c>
<w>
</w>
<q>
</q>
<b><k><t></t></k><j></j><t></t><q></q></b><x><h></h></x><r></r><k></k><i></i><t><b></b></t><z></z><x></x><p></p><u></u>
<b>
  <k>
    <t>
    </t>
  </k>
  <j>
  </j>
  <t>
  </t>
  <q>
  </q>
</b>
<x>
  <h>
  </h>
</x>
<r>
</r>
<k>
</k>
<i>
</i>
<t>
  <b>
  </b>
</t>
<z>
</z>
<x>
</x>
<p>
</p>
<u>
</u>
<c><l><i><h><z></z></h><y><k></k><o></o></y></i><a></a><x></x></l><r><y></y><k><s></s></k></r><j><a><f></f></a></j><h></h><p></p></c><h></h>
<c>
  <l>
    <i>
      <h>
        <z>
        </z>
      </h>
      <y>
        <k>
        </k>
        <o>
        </o>
      </y>
    </i>
    <a>
    </a>
    <x>
    </x>
  </l>
  <r>
    <y>
    </y>
    <k>
      <s>
      </s>
    </k>
  </r>
  <j>
    <a>
      <f>
      </f>
    </a>
  </j>
  <h>
  </h>
  <p>
  </p>
</c>
<h>
</h>
<p><q><l></l><q><k><r><n></n></r></k></q></q><x><z></z><r><k></k></r><h></h></x><c><p></p><o></o></c><n></n><c></c></p><b><c><z></z></c><u><u><f><a><d></d><q></q></a><x><i></i></x><r></r></f></u></u></b><j></j>
<p>
  <q>
    <l>
    </l>
    <q>
      <k>
        <r>
          <n>
          </n>
        </r>
      </k>
    </q>
  </q>
  <x>
    <z>
    </z>
    <r>
      <k>
      </k>
    </r>
    <h>
    </h>
  </x>
  <c>
    <p>
    </p>
    <o>
    </o>
  </c>
  <n>
  </n>
  <c>
  </c>
</p>
<b>
  <c>
    <z>
    </z>
  </c>
  <u>
    <u>
      <f>
        <a>
          <d>
          </d>
          <q>
          </q>
        </a>
        <x>
          <i>
     ...
<w><q><x></x></q><r></r><o></o><u></u><o></o></w><d><z></z><n><x></x></n><y></y><s></s><k></k><q></q><a></a></d><h><u></u><s></s><y></y><t></t><f></f></h><v><w><q></q></w><s></s><h></h></v><q><o></o><k></k><w></w></q><c></c><p><j></j></p><c><u></u></c><s></s><x></x><b></b><i></i>
<w>
  <q>
    <x>
    </x>
  </q>
  <r>
  </r>
  <o>
  </o>
  <u>
  </u>
  <o>
  </o>
</w>
<d>
  <z>
  </z>
  <n>
    <x>
    </x>
  </n>
  <y>
  </y>
  <s>
  </s>
  <k>
  </k>
  <q>
  </q>
  <a>
  </a>
</d>
<h>
  <u>
  </u>
  <s>
  </s>
  <y>
  </y>
  <t>
  </t>
  <f>
  </f>
</h>
<v>
  <w>
    <q>
    </q>
  </w>
  <s>
  </s>
  <h>
  </h>
</v>
<q>
  <o>
  </o>
  <k>
  </k>
  <w>
  </w>
</q>
<c>
</c>
<p>
  <j>
  </j>
</p>
<c>
  <u>
  </u...
<g><t><m><x><f><w><z><b><d><j></j><g><z></z><q><l><j></j><l><k></k><l><n><d></d><m></m></n></l><i><m><j></j></m></i></l></l><w><t><h><r><h></h><b></b></r></h></t><d><j></j></d><x><w><r><s><s></s></s></r></w><x></x></x></w><m><m><d></d><x><r><x><o><v></v><d><n></n></d></o></x></r></x></m></m></q></g><y></y></d></b></z></w></f></x><a></a></m></t></g>
<g>
  <t>
    <m>
      <x>
        <f>
          <w>
            <z>
              <b>
                <d>
                  <j>
                  </j>
                  <g>
                    <z>
                    </z>
                    <q>
                      <l>
                        <j>
                        </j>
                        <l>
                          <k>
                          </k>
                          <l>
                            <n>
      ...
<d><d><w><v><g><m></m></g><b><u></u><j><h><n><q><q><c></c></q></q></n></h><c></c><l><r><l></l><b><d></d><x><k><o><w><q><x></x></q></w></o></k><p></p></x><g><m></m></g></b></r></l></j><k><l></l></k><c><v><g><p><p><d><e><z><x></x></z></e><v></v></d><u><o><u></u><k></k></o></u><m><x><h><z><f></f></z></h></x><w></w></m></p></p></g></v><t><n><u><b><h></h></b></u><r><m><k><z></z></k></m><j><e><w><s></s><e><s><p></p><o></o></s><g></g></e><u></u></w></e></j></r></n></t></c></b></v></w></d></d>
<d>
  <d>
    <w>
      <v>
        <g>
          <m>
          </m>
        </g>
        <b>
          <u>
          </u>
          <j>
            <h>
              <n>
                <q>
                  <q>
                    <c>
                    </c>
                  </q>
                </q>
              </n>
            </h>
            <c>
            </c>
            <l>
              <r>
                <l>
                </l>
                <b>
            ...
str_input = input()
queue = []
indentation = 0
while(str_input != ""):
	if(str_input[1] == '/'):
		print("%s%s"%(indentation * " ", str_input[0:4]))
		queue.pop()
		str_input = str_input[4:]
		if(str_input != "" and str_input[1] == "/"):
			indentation -= 2
	else:
		print("%s%s"%(indentation * " ", str_input[0:3]))
		queue.append(str_input[1:2])
		str_input = str_input[3:]
		if(str_input != "" and str_input[0:3] != "</%s"%(queue[-1])):
			indentation += 2
