Bootstrap 3 - clear columns

clear-columns.less

.row {
    > .col-sm-4 {
        @media screen and (min-width: @screen-sm-min){
            &:nth-child(3n + 1) {
                clear: left;
            }
        }
    }
    > .col-sm-3 {
        @media screen and (min-width: @screen-sm-min){
            &:nth-child(4n + 1) {
                clear: left;
            }
        }
    }
}