Nursery Seed Packet Duplicate Codes

A community nursery packs seedlings into numbered seed packets before shipping them out each morning. The packing station's labeler is configured to stamp every packet with an integer code between 0 and n-3, inclusive, and under normal operation each of these n-2 possible codes is stamped onto exactly one packet, for a total of n packets. This morning the labeler jammed twice, so two of the codes each ended up stamped onto two separate packets instead of one, while every other code still appears on exactly one packet. You are given the codes read off all n packets, in the order they came off the belt. Identify the two codes that were stamped twice.

Input format

• Line 1: a single integer n, the number of packets.
• Line 2: n space-separated integers, the codes read off the packets in belt order.

Output format

Print the two duplicated codes, in increasing order, separated by a single space.

Constraints

• 4 <= n <= 200000
• Every code lies between 0 and n-3, inclusive.
• Every integer from 0 to n-3 appears at least once among the n codes, exactly two distinct codes appear exactly twice, and every other code appears exactly once.

4
0 1 0 1

0 1

6
1 3 0 2 1 3

1 3