Задача A+B. Сложение двух чисел

Код программы в XML:

<xml xmlns="http://www.w3.org/1999/xhtml">
<block type="variables_set" id="19" x="138" y="88">
<field name="VAR">A</field>
<value name="VALUE">
<block type="text_prompt_ext" id="20">
<mutation type="NUMBER"></mutation>
<field name="TYPE">NUMBER</field>
<value name="TEXT">
<block type="text" id="21">
<field name="TEXT">Введите первое число</field>
</block>
</value>
</block>
</value>
<next>
<block type="variables_set" id="22">
<field name="VAR">B</field>
<value name="VALUE">
<block type="text_prompt_ext" id="23">
<mutation type="NUMBER"></mutation>
<field name="TYPE">NUMBER</field>
<value name="TEXT">
<block type="text" id="24">
<field name="TEXT">Введите второе число</field>
</block>
</value>
</block>
</value>
<next>
<block type="variables_set" id="25">
<field name="VAR">C</field>
<value name="VALUE">
<block type="math_arithmetic" id="26">
<field name="OP">ADD</field>
<value name="A">
<block type="variables_get" id="27">
<field name="VAR">A</field>
</block>
</value>
<value name="B">
<block type="variables_get" id="28">
<field name="VAR">B</field>
</block>
</value>
</block>
</value>
<next>
<block type="text_print" id="29">
<value name="TEXT">
<block type="text_join" id="30">
<mutation items="2"></mutation>
<value name="ADD0">
<block type="text" id="31">
<field name="TEXT">Сумма введенных двух чисел = </field>
</block>
</value>
<value name="ADD1">
<block type="variables_get" id="32">
<field name="VAR">C</field>
</block>
</value>
</block>
</value>
</block>
</next>
</block>
</next>
</block>
</next>
</block>
</xml>