# homework_Array.py

array_num = input('請輸入數列的前四項並用空格隔開: ')
array = array_num.split()
# 提出上一行輸入的數列


iArray_1 = int(array[1])
iArray_2 = int(array[2])
iArray_3 = int(array[3])
# 提出陣列中後三項的值

if iArray_3 - iArray_2 == iArray_2 - iArray_1:
    array.append(iArray_3 + (iArray_3 - iArray_2))

    num_a = 0
    for i in array:
        print(int(array[num_a]), end=' ')
        num_a += 1
# 循環輸出數列，且數列為等差級數

elif iArray_3 // iArray_2 == iArray_2 // iArray_1:
    array.append(iArray_3 * (iArray_3 // iArray_2))

    num_a = 0
    for i in array:
        print(int(array[num_a]), end=' ')
        num_a += 1
# 循環輸出數列，且數列為等比級數