# -----------------------------------------------
# Function: Return every even-numbered line
# (lines 2, 4, 6, 8, ... using human numbering)
# -----------------------------------------------
def onlyEvenLines(lines):
	return []

# -----------------------------------------------
# Function: Count occurrences of 'l' or 'L'
# -----------------------------------------------
def countLs(lines):
	return 0

# -----------------------------------------------
# Function: Return lines with at least 20 characters
# -----------------------------------------------
def filterLongLines(lines):
	return []


# -----------------------------------------------
# Main Program
# -----------------------------------------------
f = open("data.txt")
lines = f.readlines()
f.close()

# --- Even-numbered lines ---
answer = onlyEvenLines(lines)
print("----------------------------------------")
print("Here are the even-numbered lines")
print("----------------------------------------")
for line in answer:
    print(line, end="")
print("\n\n")


# --- Count Ls ---
answer2 = countLs(lines)
print("----------------------------------------")
print(f"There are {answer2} Ls in the file")
print("----------------------------------------")
print("\n\n")


# --- Long lines ---
answer3 = filterLongLines(lines)
print("----------------------------------------")
print("Here are the lines with 20+ characters")
print("----------------------------------------")
for line in answer3:
    print(line, end="")
print()