<style>
.container {
  width: 100px;
  background-color: green;
}

.float {
  float: left;
  width: 30px;
  height: 100px;
}

.float_avoider {
  overflow: hidden;
  height: 50px;
}
</style>
<div class=container>
  <div class=float></div>
  <div class=float_avoider></div>
  <div class=float_avoider></div>
</div>