s = input()
a = len(s)
b = ""
c = ""
for i in range(int(a/3-(a%3)/3)):
  b = ","+s[a-3-i*3:a-i*3]+b
b = s[0:a%3] + b

if(a%3==0):
  m = a + a/3
  c = b[1:int(m)]
else:
  c = b
print(c)