set the first radio button is checked in handlebars template

How can i get a easy and clear way that set the first radio button is checked in Handlebars template. tks

template:

<form>
    {{#each this}}
        <input value="{{value}}" />
     {{/each}}
</form>

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

expect render:

<form>
    <input value="val 1" checked />
    <input value="val 2" />
    <input value="val 3" />
</form>

thanks all.