Most Frequent Packet Identifier

You are given a log of packet identifiers. Your task is to determine the packet identifier that occurs most frequently. Formally, given an integer \(N\) and a list of \(N\) integers \(a_1, a_2, \ldots, a_N\), find the identifier with the maximum frequency. If there are multiple identifiers with the same highest frequency, output the one that appears first in the list. If \(N = 0\), print None.

Example:

Input:
7
1 2 1 2 3 1 3
Output:
1

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In the above example, the identifier 1 appears 3 times while 2 and 3 appear fewer times. Use standard input and output.

inputFormat

The first line contains a single integer \(N\) denoting the number of packet identifiers.

The second line contains \(N\) space-separated integers representing the packet identifiers.

outputFormat

Output a single integer which is the most frequent packet identifier. If there are no packets (i.e. \(N = 0\)), print None.

## sample

7
1 2 1 2 3 1 3

1

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