For an asymmetrical social network, you are given a dataset D where lines consist of (a,b) which means user a follows user b. Write a MapReduce program (Map and Reduce separately) that outputs the list of all user pairs (x,y) who satisfy the following three conditions simultaneously: i) x has fewer than 100 M followers, ii) y has fewer than 100M followers, iii) x and y follow each other, and iv) the sum of x's followers and y's followers (double-counting common followers that follow both x and y is ok) is 100 M or more. Your output should not contain duplicates (i.e., no (x,y) and (y,x)).