def validate_is_positive_numeric(val):
    try:
        val = float(val)
        if val <= 0:
            print("Enter a valid positive value")
            return None, False
    except ValueError:
        print("Enter a valid numeric value")
        return None, False

    return val, True


def read_input(text):
    value, success = validate_is_positive_numeric(input(text))
    if not success:
        read_input(text=text)

    return value


def calculate_average(macro_name, total_quantity, total_patients):
    avg = total_quantity/int(total_patients)
    print("Amount of {} (g) required : {}".format(macro_name, avg))


num_patients = read_input("Enter the number of patients: ")


protein, fats, carbs, kilojoules = 0, 0, 0, 0
for _ in range(int(num_patients)):
    protein += read_input("Amount of protein (g) required: ")
    fats += read_input("Amount of fats (g) required: ")
    carbs += read_input("Amount of carbohydrates (g) required: ")
    kilojoules = 4.18*(4*protein + 4*carbs + 9.30*fats)

calculate_average(macro_name="Protein", total_quantity=protein, total_patients=num_patients)
calculate_average(macro_name="Fats", total_quantity=fats, total_patients=num_patients)
calculate_average(macro_name="Carbohydrates", total_quantity=carbs, total_patients=num_patients)
calculate_average(macro_name="Kilojoules", total_quantity=kilojoules, total_patients=num_patients)