**Time limit:**1.00 s**Memory limit:**512 MB

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

Output:

3