from re import M import sys # for line in sys.stdin: # a = line.split() # print(int(a[0]) + int(a[1])) s = input().strip() s= list(s) m = len(s) num = 0 new_list = [] for i in range(m): c = s[m-i-1] num += 1 new_list.insert(0,c) if num == 3: new_list.insert(0,',') num = 0 if new_list[0] == ',': # ne...