list1 = list(set(arr))

list1.remove(max(list1))

print(max(list1))

    with this solution all the test case where passed 

one more way it can be solved list1 = list(set(arr)) print(list1[-2])

if name == 'main': n = int(input()) arr = map(int, input().split())

arr = list(set(arr))
arr.remove(max(arr))       # you can use pop function too : )
print(max(arr))

print(sorted(set(arr), reverse=True)[1])

if name == 'main': n = int(input()) arr = list(set(map(int, input().split()))) arr.sort() print(arr[-2])