def main():
    z = input()[::-1]
    k = 0
    s = ''
    for c in z:
        k += 1
        s = s+c
        if k == 3:
            k = 0
            s += ','

    s = s[::-1]
    if s[0] == ',':
        s = s[1:]
    print(s)


if __name__ == '__main__':
    main()