# Write a function that takes a string and a substring and
# removes the second instance of the substring from the string
# without using any built-in functions/methods besides len()
# (i.e. you may NOT use .index()).
# The substring will be at most three characters long.
#
# After completing the solution without using built-in functions/methods,
# rewrite a function to use built-in functions/methods.
# Then, compare both solutions.

def removeSecond(l, n):
    string = l
    substring = n
    count = 0

    for i in range(0, len(string)):
        if string[i:(i + len(substring))] == substring:
            count += 1
            if count == 2 :
                string = string[0:i] + string[i + len(substring): ]
                #break      # how else can we break the loop
    return string



print(removeSecond('bird', 'i'))       # bird
print(removeSecond('bird', 'x'))       # bird
print(removeSecond('ibiridi', 'i'))    # ibridi
print(removeSecond('kiaeb', 'iae'))    # kiaeb
print(removeSecond('kiaebiaeriaediae', 'iae'))    # kiaebriaediae
print(removeSecond('kiaebiariaediaeia', 'iae'))   # kiaebiardiaeia