<?php
	    $reduce = substr(date('YmdHis', time()), 2);
	    $arr_date = str_split($reduce);
	    $arr1 = str_split("cdefgab");
	    $uid = "";
	    for($i = 0; $i<12; $i++){
	        $uid .= $arr1[rand(0, 6)];
	        $uid .= $arr_date[$i];
	    }
	    echo $uid;