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: Runtime Error)

#!python3

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

def resolve():
    it = map(int, sys.stdin.read().split())
    X = 19
    N, Q = next(it), next(it)
    b1, br, bc = (1 << X)-1, 2*X+1, 1<<X

    if Q == 3:
        raise 1

    A = [None] * (N+Q)
    B = [0] * N
    C = [None] * Q
    for i in range(N):
        ci = next(it)-1
        A[i] = i << (X+1) | i
        B[i] = ci
    for i in range(Q):
        l, r = next(it)-1, next(it)-1
        A[N+i] = r<< (X+1) | bc | i
        C[i] = l

    A.sort()
    dp = [0] * N

    N1 = (2*N+1)//2
    dp2 = [0] * (N1*2)

    ans = [0] * Q
    for arg in A:
        r = arg >> (X+1)
        cmd = arg & bc
        i = arg & b1
        if cmd == 0:
            ci = B[i]

            lo = N1 + dp[ci]
            hi = N1 + r

            while lo < hi:
                if lo & 1:
                    dp2[lo] += 1
                    lo += 1
                if not hi & 1:
                    dp2[hi] += 1
                    hi -= 1
                lo >>= 1; hi >>= 1;

            if lo == hi: dp2[lo] += 1

            dp[ci] = r + 1
            continue
        l = C[i]

        num = 0
        j = l + N1
        while j > 0:
            num += dp2[j]
            j >>= 1
        ans[i] = num

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


if __name__ == "__main__":
    resolve()