Problem:
Score : 600 points

Problem Statement

We have N colored balls arranged in a row from left to right; the color of the i-th ball from the left is c_i.

You are given Q queries. The i-th query is as follows: how many different colors do the l_i-th through r_i-th balls from the left have?

Constraints

1\leq N,Q \leq 5 \times 10^5

1\leq c_i \leq N

1\leq l_i \leq r_i \leq N

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N Q
c_1 c_2 \cdots c_N
l_1 r_1
l_2 r_2
:
l_Q r_Q

Output

Print Q lines. The i-th line should contain the response to the i-th query.

Sample Input 1

4 3
1 2 1 3
1 3
2 4
3 3

Sample Output 1

2
3
1

The 1-st, 2-nd, and 3-rd balls from the left have the colors 1, 2, and 1 - two different colors.

The 2-st, 3-rd, and 4-th balls from the left have the colors 2, 1, and 3 - three different colors.

The 3-rd ball from the left has the color 1 - just one color.

Sample Input 2

10 10
2 5 6 5 2 1 7 9 7 2
5 5
2 4
6 7
2 2
7 8
7 9
1 8
6 9
8 10
6 8

Sample Output 2

1
2
2
1
2
2
6
3
3
3

Solution in PyPy3 (7.3.0) (judge verdict: Time Limit Exceeded)

#!python3

import sys
iim = lambda: map(int, sys.stdin.readline().rstrip().split())
from bisect import bisect

def resolve():
    it = map(int, sys.stdin.read().split())
    N, Q = next(it), next(it)
    C = [next(it) for i in range(N)]
    D = list(zip(it, it, range(Q)))

    D.sort(key=lambda x: (x[1], x[0]), reverse=True)

    C1 = [[-1, []] for i in range(N)]
    rx = D[0][1]
    for i, ci in zip(range(rx), C):
        x = C1[ci-1]
        x[1].append(x[0])
        x[0] = i
    C2 = C1[:]
    C2.sort()

    ans = [0] * Q
    rj = rx
    for li, ri, i in D:
        if ri < rj:
            for j in reversed(range(ri, rj)):
                cj = C[j] - 1
                x = C1[cj]
                x[0] = x[1].pop()
            C2.sort()
            rj = ri

        k = bisect(C2, [li-1,])
        ans[i] = N - k

    print(*ans, sep="\n")


if __name__ == "__main__":
    resolve()