<form class="navbar-form pull-right">

                    <div class="form-group form-group-sm">

                    <input type="email" class="form-control input" id="email" name="email" placeholder="jane.doe@example.com">
                    </div>

                    <input type="submit" class="btn btn-sm" name="submit" value="Submit" id="submit"/>
                    </div>

                </form>

.form-control {
border-radius: 0;
}