how to include both uppercase and lowercase in python code example

Example 1: from uppercase to lowercase python

# By Alan W. Smith and Petar Ivanov
s = "Kilometer"
print(s.lower())

Example 2: python 3 calculate uppercase lowercase letter

world = input()
upper,lower = 0,0

for i in world:
    upper+=i.isupper()
    lower+=i.islower()

print("UPPER CASE {0}\nLOWER CASE {1}".format(upper,lower))