Find the Missing Number

You are given an integer n which represents the total count of numbers from 1 to n. You are also provided with n-1 numbers in random order, representing all the numbers from 1 to n except one missing number. Your task is to find the missing number.

Recall that the sum of the first n natural numbers is given by the formula: \( S = \frac{n(n+1)}{2} \). Use this property to determine the missing number.

Example:

Input:
5
1 2 4 5
Output:
3

</p>

inputFormat

The input is given via stdin and consists of two lines.

• The first line contains a single integer n, representing the total count of numbers if none were missing.
• The second line contains n-1 space-separated integers.

It is guaranteed that the numbers are unique and between 1 and n (inclusive) except for one missing number.

outputFormat

Output the missing number via stdout as a single integer.

## sample

5
1 2 4 5

3