python – Why is my code showing a wrong smallest number

list = ()

print('Please input numbers, when your done type "done".')
while True:
    x = input('> ')
    if x == 'done':
        break
    list.append(x)

big = list(0)
small = list(0)

for number in list:
    if number > big:
        big = number
    if number < small:
        small = number

print ("The largest number is:", big)
print ("The smallest number is:", small)

I wrote this code to find and print the smallest and largest numbers from a list of inputs.
I wrote these numbers as inputs: 10, 20, 30, -10, -20, -30, the smallest number must be -30 but the output is -10.