Bootstrap 4

HTML

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-alpha.2/css/bootstrap.min.css">
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-alpha.2/js/bootstrap.min.js"></script>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootswatch/3.3.7/flatly/bootstrap.min.css">
<nav class="navbar navbar-default navbar-light bg-faded">

  <a class="navbar-brand" href="#">My Brand</a>
    <div class="mr-auto">
      <a href=""><button class="btn btn-outline-success my-2 my-sm-0" type="submit">Search</button></a>
</div>
</nav>

CSS

.mr-auto{
  float:right;
  margin-top:7px;
}