// 27 lines 18 code 4 comments 5 blanks

/**
multi-line
*/
div {
  width: calc(99.9% * 1/3 -  (30px - 30px * 1/3)); 
}

div:nth-child(1n) {
  float: left; 
  margin-right: 30px; 
  clear: none; 
}

div:last-child {
  margin-right: 0; 
}

div:nth-child(3n) {
  margin-right: 0; 
  float: right; 
}

div:nth-child(3n + 1) {
  clear: both; 
}