add_substract_divide_multiply and AVERAGE, shoppinlist,area

print("Hi, I am Marvin, your personal bot.")
phrase = input("Whats your name ?  >")
print(" Morning " + phrase)
print("Do you want to divide, multiply , add, substract , average, shopping list, area ?")
command = input("How can I help ? >")
if command == "divide" or command == "plus":
    print("Let's divide 2  numbers.")
    input1 = input("Number 1> ")  # input numbers are strings#
    input2 = input("Number 2> ")
    number1 = int(input1)  # use int to convert string to integer#
    number2 = int(input2)
    result = number1 / number2    # by using add #
    output = str(result)  # result of operation#
    print(input1 + " / " + input2 + " = " + output)
elif command == "multiply":
    print(" Let's multiply 2  numbers.")
    input1 = input("Number 1> ")
    input2 = input("Number 2> ")
    number1 = int(input1)
    number2 = int(input2)
    result = number1 * number2
    output = str(result)
    print(input1 + " * " + input2+" = " + output)
elif command == "add":
    print(" Let's add 2  numbers.")
    input1 = input("Number 1> ")
    input2 = input("Number 2> ")
    number1 = int(input1)
    number2 = int(input2)
    result = number1 + number2
    output = str(result)
    print(input1 + " + " + input2+" = " + output)
elif command == "substract":
    print(" Let's substract 2  numbers.")
    input1 = input("Number 1> ")
    input2 = input("Number 2> ")
    number1 = int(input1)
    number2 = int(input2)
    result = number1 - number2
    output = str(result)
    print(input1 + " - " + input2+" = " + output)


elif command == "average":
    print("NOW find average")
    how_many = input("How many numbers > ")
    how_many = int(how_many)
    total = 0
    for number_count in range(how_many):
        number = input("Enter number " + str(number_count) + "?")
        total = total + int(number)
    result = total /how_many
    print("the average = " + str(result))
elif command == "area":
    print("Let's find the area of a rectangle.")
    input1 = input("Enter the width:")
    input2 = input("Enter the height: ")
    number1 = int(input1)
    number2 = int(input2)
    result = number1 * number2
    output = str(result)
    print("The area of a " + input1 + "  by " + input2 + " rectangle  is = " + output)

elif command == "shopping list":
    print ("Now let's go shopping")
    shopping =  []
    total_cost = 0
    how_many = input("how many items in your list ?")
    how_many = int(how_many)

    for item_number in range(how_many):
        item = input("What is item number " + str(item_number + 1) + "?")
        cost = input("What does " + item + " cost in euros? >")
        cost = float(cost)
        shopping.append(item)
        total_cost = total_cost + cost
    print(" You have to pay " + str(total_cost))
else:
    print("Sorry I don't understand")
print("Well done" + phrase)