align long text in flex box same way as short text

how can I let flex box stay same when it has long text or short text

html

<div class="a"><div class="b" style="background-color:red"></div><div class="b" style="background-color:yellow"></div><div class="b" style="background-color:green">       aaaaaaaaaaaaaaa</div></div>

css

.a {   display:flex;   justify-content: space-between}.b {}