list1 = [10, 20, 4, 45, 99]
mx=max(list1[0],list1[1])
secondmax=min(list1[0],list1[1])
n =len(list1)
for i in range(2,n):
if list1[i]>mx:
secondmax=mx
mx=list1[i]
elif list1[i]>secondmax and
mx != list1[i]:
secondmax=list1[i]
print("Second highest number is : ",
str(secondmax))
Output:-
Second highest number is : 45