You are given an array that contains each number between ~1 \dots n~ exactly once. Your task is to collect the numbers from ~1~ to ~n~ in increasing order.

On each round, you go through the array from left to right and collect as many numbers as possible. What will be the total number of rounds?

Input

• The first line has an integer ~n~: the array size.

The next line has ~n~ integers ~x\_1,x\_2,\dots,x\_n~: the numbers in the array.

Output

• Print one integer: the number of rounds.

Constraints

• ~1 \le n \le 2 \cdot 10^5~

Example Input

5
4 2 1 5 3

Example Output

3