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)

#!usr/bin/env python3
import sys
def LI(): return [int(x) for x in sys.stdin.readline().split()]
def LIR(n):
    return [LI() for i in range(n)]

def solve():
    def add(i,x):
        while i < len(bit):
            bit[i] += x
            i += i&-i
    def sum_(i):
        res = 0
        while i > 0:
            res += bit[i]
            i -= i&-i
        return res
    n,Q = LI()
    c = LI()
    c = [0]+c
    q = LIR(Q)
    q = [[i,q[i]] for i in range(Q)]
    q.sort(key = lambda x:x[1][1])
    bit = [0]*(n+2)
    i = 1
    p = [None]*(n+1)
    ans = [0]*Q
    s = 0
    for ind,(l, r) in q:
        l -= 1
        while i <= r:
            ci = c[i]
            j = p[ci]
            if j is not None:
                add(j,1)
            else:
                s += 1
            p[ci] = i
            i += 1
        ans[ind] = s-l+sum_(l)
    for i in ans:
        print(i)
    return

#Solve
if __name__ == "__main__":
    solve()