题解 | #字母大小写转换#
字母大小写转换
https://www.nowcoder.com/practice/850ebd30a2a34cfc87199da3fc15786a
while True:
try:
m = input()
for item in m:
if item.isupper():
print(item.lower())
elif item.islower():
print(item.upper())
except:
break
