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CSES Problem Set

Missing Number


Task | Statistics


CSES - 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
Example

Input:
5
2 3 1 5


Output:
4