python 找出第二大值

listNum = []

num = 0
while num < 5:
    val = int(input())
    listNum.append(val)
    num += 1
print(listNum)

'''
#升序排序
listNum.sort()

count = listNum.count(listNum[len(listNum) - 1])
c = 0
while c < count:
    listNum.pop()
    c += 1

print(listNum[len(listNum) - 1])
'''

if listNum[0] >= listNum[1]:
    max = listNum[0]
    sec = listNum[1]
else:
    max = listNum[1]
    sec = listNum[0]

index = 2
while index < len(listNum):
    if listNum[index] >= sec:
        sec = listNum[index]
    if listNum[index] >= max:
        sec = max
        max = listNum[index]
    index += 1

print(sec)