Modify class name with XPATH

Basically, I have an Html file full of Divs without major variations between them. So:

<div id="all-divs" class="number1">
   <div class="generaldiv">
      <div class="randomclass">
         <input value="2874973" name="foo1" class="foo2" id="fooid" type="checkbox"/>
         <label class="rand" for="rand2-2874973">Text</label>
      </div>
   </div>
</div>
<div id="all-divs" class="number2">
   <div class="generaldiv">
      <div class="randomclass">
         <input value="2874974" name="foo1" class="foo2" id="fooid" type="checkbox"/>
         <label class="rand" for="rand2-2874973">Text</label>
      </div>
   </div>
</div>

Class numbers change dynamically so there is no way to know them before reviewing the file.

At this time, I need to do the following:

From

<div id="all-divs" class="number1">

A

<div id="all-divs-2874973" class="number1">

I have managed to extract the input number without problems, using Xpath:

        $finder = new DomXPath($dom);


        $nodes = $finder->query('//input[@class="foo2"]');


        $nodevalue = $nodes->item(0);

        $atribute = $nodevalue->getAttribute('value');

However, I need to modify the DIV all-divs without success as I mentioned earlier.

I thank you in advance for your help.