NoOfStudents = int(input("Enter number of students: "))
list1 = []
list2 = []
for i in range(0,NoOfStudents):
    n = float(input("Enter student percentage: "))
    list2.append(n)
for j in list2:
    if(j != -1):
        list1.append(j)
        
def avg():
	sum1 = 0
	for i in list1:
		sum1 = sum1 + i
	avg = sum1/NoOfStudents
	print("Sum is: ",sum1)
	print("Average is: ",avg)

def largest():
	largest = None
	for i in list1:
		if(largest==None or largest<i):
			largest = i
	print("The highest marks is: ",largest)

def smallest():
	smallest = None
	for i in list1:
		if(smallest==None or smallest>i):
			smallest = i
	print("The lowest marks is: ",smallest)
     
def absent():
    abs = 0
    for j in list2:
        if(j == -1):
            abs = abs + 1
    print("Number of absent students are: ",abs)

def frequency():
    temp = 0
    for i in list1:
        max1 = 0
        for j in range(0,len(list1)):
            if(i == list1[j]):
                max1 = max1 + 1
            else:
                continue
        if(max1>temp):
            temp = max1
            k = i
        else:
            continue
    print("Marks with highest frequency is: ",k)
    print("Frequency of the number is: ",temp)

flag = 1
while flag == 1:
    print("\nThe options are: ")
    print("1. Total and average marks are: ")
    print("2. Highest marks among the students: ")
    print("3. Lowest marks among the students: ")
    print("4. Number of absent students: ")
    print("5. Marks with highest frequency is: ")
    print("6. Exit")
    ch = int(input("Enter choice: "))
    if(ch == 1):
        avg()
    elif(ch == 2):
        largest()
    elif(ch == 3):
    	smallest()
    elif(ch == 4):
        absent()
    elif(ch == 5):
        frequency()
    elif(ch == 6):
        flag = 0
    elif(ch>6 or ch<1):
        print("Enter valid choice")