question-missing-number.md

Time limit: 1.00 s    Memory limit: 512 MB

You are given all numbers between 1, 2 , $\ldots$, $n$ except one. Your task is to find the missing number.

Input

The first input line contains an integer $n$.

The second line contains $n$ - 1 numbers. Each number is distinct and between 1 and $n$ (inclusive).

Output

Print the missing number.

Constraints

• 2 $\leq$ $n$ $\leq$ 2 $\cdot$ $10^{5}$

Example

Input:
5
2 3 1 5

Output:
4

Solution