Problem:
Score : 500 points

Problem Statement

You are given a sequence (P_1,P_2,...,P_N) which is a permutation of the integers from 1 through N.
You would like to sort this sequence in ascending order by repeating the following operation:

Choose an element in the sequence and move it to the beginning or the end of the sequence.

Find the minimum number of operations required.
It can be proved that it is actually possible to sort the sequence using this operation.

Constraints

1 \leq N \leq 2\times 10^5

(P_1,P_2,...,P_N) is a permutation of (1,2,...,N).

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N
P_1
:
P_N

Output

Print the minimum number of operations required.

Sample Input 1

4
1
3
2
4

Sample Output 1

2

For example, the sequence can be sorted in ascending order as follows:

Move 2 to the beginning. The sequence is now (2,1,3,4).

Move 1 to the beginning. The sequence is now (1,2,3,4).

Sample Input 2

6
3
2
5
1
4
6

Sample Output 2

4

Sample Input 3

8
6
3
1
2
7
4
8
5

Sample Output 3

5

Solution in Ruby (2.3.3) (judge verdict: Time Limit Exceeded)


input = STDIN.readlines().map(&:to_i)

num = input[0].to_i

arr = input[1..-1]


max = 0
maxnum = 0

arr.each_with_index do |n, i|
  last = n
  count = 1
  arr[i..0].each_with_index do |v, j|
    if v == (last - 1)
      last = v
      count += 1
    end
  end

  last = n
  arr[i..-1].each_with_index do |v, j|
    if v == (last + 1)
      last = v
      count += 1
    end
  end

  if count > maxnum
    maxnum = count
  end
end

puts num - maxnum