while True: try: num = int(input()) num_list = [] result = 2 num_result = 0 for i in range(0, num): num_list.append(result+3*i) for j in range(len(num_list)): num_result += num_list[j] print(num_result) except: break
while True: try: num = int(input()) num_list = [] result = 2 num_result = 0 for i in range(0, num): num_list.append(result+3*i) for j in range(len(num_list)): num_result += num_list[j] print(num_result) except: break