Bài 2

#Tao string s
s = 'hello anh Long'
#Tao s1 sao cho thuong thanh Hoa, Hoa thanh thuong
s1 =''
for word in s:
    if word.isupper():
        s1 += word.lower()
    else:
        s1 += word.upper()
print(s1)