#coding: utf-8
n = list(input())
n.reverse()
cnt = 0
for i in range(0, len(n)-1, 3):
    n.insert(3*(cnt+1)+cnt, ",")
    cnt += 1
n.reverse()
if n[0] == ",":
    print("".join(n[1:]))
else:
    print("".join(n))