list1 = [12, 2, 3, 4, 1]
len = len(list1)

for i in range(1, len):
    for j in range(0, len - i):
        if list1[j] > list1[j + 1]:
            # tem=0
            # tem = list1[j]
            # list1[j] = list1[j + 1]
            # list1[j] = tem
            list1[j], list1[j + 1] = list1[j + 1], list1[j]
print(list1)