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 Python (3.8.2) (judge verdict: Time Limit Exceeded)

'''
自宅用PCでの解答
'''
import math
#import numpy as np
import itertools
import queue
import bisect
from collections import deque,defaultdict
import heapq as hpq
from sys import stdin,setrecursionlimit
#from scipy.sparse.csgraph import dijkstra
#from scipy.sparse import csr_matrix
ipt = stdin.readline
setrecursionlimit(10**7)
mod = 10**9+7
alp = "abcdefghijklmnopqrstuvwxyz"

def Mo(n,q,c,qi,base):
    ans = [0]*q
    ln = [-1]*(n+1)

    #BITの構成
    BIT = [0]*(n+1)
    def BIT_query(idx):
        res_sum = 0
        while idx > 0:
            res_sum += BIT[idx]
            idx -= idx&(-idx)
        return res_sum
    def BIT_update(idx,x):
        while idx <= n:
            BIT[idx] += x
            idx += idx&(-idx)
        return

    #Rが小さい方から見ていく,BITによる累積和の処理を含む
    pr = 0
    for ist in qi:
        i = ist%(base)
        l = (ist//(base))%(base)
        r = ist//(base)**2
        for j in range(pr,r):
            cj = c[j]
            ij = ln[cj]
            if ij != -1:
                BIT_update(ij,-1)
            ln[cj] = j+1
            BIT_update(j+1,1)
        pr = r
        ans[i] = BIT_query(r)-BIT_query(l-1)
    return ans

def main():
    n,q = map(int,ipt().split())
    c = [int(i) for i in ipt().split()]
    qi = []
    base = 10**6+1
    for i in range(q):
        l,r = map(int,ipt().split())
        qi.append(r*(base**2)+l*base+i)
    qi.sort()

    ans = Mo(n,q,c,qi,10**6+1)

    for i in ans:
        print(i)

    return None

if __name__ == '__main__':

    main()