Find the Missing Number

Given an integer \( n \) and an array of \( n-1 \) unique integers from 1 to \( n \), one integer is missing. You are required to determine the missing integer. Recall that the sum of the first \( n \) natural numbers is given by \( \frac{n(n+1)}{2} \), so the missing number can be computed by subtracting the sum of the array from this total.

Example:

Input:
5
1 2 4 5
Output:
3

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In the above example, the total sum from 1 to 5 is \(15\), and the sum of the given numbers is \(12\). Thus, the missing number is \(15 - 12 = 3\).

inputFormat

The input is provided via standard input (stdin) in the following format:

1. The first line contains a single integer \( n \), representing the range of numbers from 1 to \( n \).
2. The second line contains \( n-1 \) space-separated integers, representing the array of numbers with one missing element.

outputFormat

The output should be printed to standard output (stdout) and must be a single integer representing the missing number.

## sample

5
1 2 4 5

3

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