n = input()

listed_m = list(str(n))
listed_m.reverse()

list_buf = []

for i in range(len(listed_m)):
    if i % 3 == 0 and i != 0:
        list_buf.append(',')
    
    list_buf.append(listed_m[i])
        
list_res = list(reversed(list_buf))
res = ''.join(list_res)

print(res)