# This program:
# - gets a string from the user.
# - creates a new string, equal to what the user typed, except that
#   the third letter is "A".
# - prints the new string.

my_string = input("please enter a string: ")

if (len(my_string) >= 3):
    # convert string to list, and make the desired change
    # (change third letter to an "A")
    my_list = list(my_string)
    my_list[2] = "A";

    # create a string out of the characters in the list
    new_string = ""
    for character in my_list:
        new_string = new_string + character

    my_string = new_string


print("the modified string is", my_string)