LOOP_COUNT = 1_000_000 EXPECTED_CHECKSUM = 3_500_013 LIVE_STATE = {"tag": "live", "payload": {"digits": [2, 7, 1, 8, 2, 8, 1, 8]}} CACHED_STATE = {"tag": "cached", "payload": {"digits": [1, 6, 1, 8, 0, 3, 4, 5]}} def configured_loop_count() -> int: try: value = int(input().strip()) except (EOFError, ValueError): return LOOP_COUNT return value if value > 0 else LOOP_COUNT def select_state(i: int) -> dict[str, object]: return LIVE_STATE if i % 2 == 0 else CACHED_STATE def state_digit(state: dict[str, object], index: int) -> int: if state["tag"] == "missing": return 0 payload = state["payload"] assert isinstance(payload, dict) digits = payload["digits"] assert isinstance(digits, list) return digits[index] def enum_struct_payload_loop(limit: int) -> int: i = 0 acc = 13 while i < limit: acc += state_digit(select_state(i), i % 8) acc = acc - 1_000_000_000 if acc > 1_000_000_000 else acc i += 1 return acc def main() -> int: result = enum_struct_payload_loop(configured_loop_count()) print(result) return 0 if result == EXPECTED_CHECKSUM else 1 if __name__ == "__main__": raise SystemExit(main())