Bootcamp Programming Python

#Message to the user to enter a list of integers. The user input will be stored as a string of integers seperated by spaces
input_string = input("Enter a list of integers separated by space. Your Input : ")
#initializing counter flag to check for number of user attempts to provide input
counter = 0
#looping till the user provides the required input or runs out of attempts. After the initial mistake user is given 2 more chances
while counter < 2 and not (input_string.replace(" ", "").isdigit() and len(input_string.replace(" ", "")) > 1):
    print("Wrong entry.")
    #inform user they have reached their last atempt.
    if counter == 1:
        msg = "Only enter integers seperated by space. Last chance. Your Input : "
    #remind user to only enter integers seperated by space
    else:
        msg = "Only enter integers seperated by space. Your Input : "
    #get user input as a string of integers seperated by space
    input_string = input(msg)
    counter = counter + 1
#check if the input string contains only digits after removing the space. Proceed to calculation only if this satisfies
if input_string.replace(" ", "").isdigit():
    #split input string by space and store it as a list
    input_list = input_string.split()
    #typecast list items into integers
    input_list = [int(i) for i in input_list]
    #initialize lists to store the calculation outputs
    prod_even = []
    sum_odd = []
    #looping over the range of input integer list, pair each element of the list with every other element in the list
    for i in range(len(input_list)):
        for j in range(i+1,len(input_list)):
            #check if a multiplied pair of integers is even
            if (input_list[i] * input_list[j])% 2 == 0:
                #append the satisfying pair to the product even list
                prod_even.append([input_list[i],input_list[j]])
            #check if the summed pair of integers is odd
            if (input_list[i] + input_list[j])% 2 != 0:
                #append the satisfying pair to the sum odd list
                sum_odd.append([input_list[i],input_list[j]])
    #print the output of the calculation for the user
    print("\nProduct Even pairs:")
    #print the pair of integers whose product is even
    for i in prod_even:
        print(str(i[0]) + "," + str(i[1]))
    print("\nSum Odd pairs:")
    #print the pair of integers whose sum is odd
    for i in sum_odd:
        print(str(i[0]) + "," + str(i[1]))
else:
    print("Wrong entry.")