Based on the challenge coded the script below,
def main():
x = 1
y = 2
answer = 0
while x <= 666:
# Perform the calculation
answer += (x y) + int(f"{x}{y}")
# Increment x for the next iteration
x += 1
# Print the final answer in the flag format
print(f"KCTF{{{answer}}}")
if name == "main":
main()