class Solution:
def maximumSwap(self, num: int) -> int:
if num <= 9:
return num
ans = num
num = list(str(num))
for i in range(len(num)):
for j in range(i + 1, len(num)):
num[i], num[j] = num[j], num[i]
ans = max(ans, int(''.join(num)))
num[i], num[j] = num[j], num[i]
return ans