def main():

    n = list(input())
    
    count = 0
    
    #print(dis)
    for i in range(len(n) // 3 ):
        #print(i)

        count += 1
        
        #if len(n) % 3 == 0:
        #    n.insert(-3 * (count - 1), ',')
        #else:
        n.insert((-3 * count - i), ',')
        
    if n[0] == ',':
        del n[0]
        
    print(*n, sep = '')




if __name__ == '__main__':
    main()