实现报数功能，如一群人围成圈，分别编号。第一号人报数1，第3号报数2，第6号报数3。。。每次报数的人出对。求得最后一个出对的人-Reported that the number of realized functions, such as circle with a group of people were numbered. No. someone reported that the number 1, number 2, No. 3 Report, Report No. 6, Number 3. . . Each time the number of people reported a pair. Obtain the last person out of