A list of digits is formed by repeatedly writing the digits and from left to right, beginning . Every second digit is then erased from the list (i.e., the nd, th, th, digits from the left). From the resulting list, every third digit is erased (i.e., the rd, th, th, digits from the left in what remained). Finally, every fourth digit is erased from what remained at that point. What is the sum of the three digits that were then in the positions , , and ?
4
5
6
7
8