what is the big-O performance of the below functions?

1.

def sum(n):

k = 0

for i in range(n):

k = k + i

for j in range (n):

k = k - 1

return k

2.

def printTime(n) :

months = n * 12

days = n * 365

print (n, 'years = ' , months, 'months, or approx.', days, 'days.')

return

3.

def sum2(n):

i = n

k = 0

while i > 1:

k = k + i

i = i // 2

return k

4.

def mult(n):

a = 5

for i in range(n):

for j in range(n):

x = x * a

y = y * x

z = z * i

for k in range(n):

z = a * z + 45

z = z + 45

return z