CSES Problem Set

# Missing Number

CSES - Missing NumberCSES - Missing Number

 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 $1,2,\ldots,n$.

Output

Print the missing number.

Constraints
• $2 \le n \le 5 \cdot 10^5$
Example

Input:
5 2 3 1 5

Output:
4