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)

mod = 1000000007
eps = 10**-9


def main():
    import sys
    input = sys.stdin.buffer.readline

    class Bit:
        def __init__(self, n):
            self.size = n
            self.tree = [0] * (n + 1)

        def sum(self, i):
            s = 0
            while i > 0:
                s += self.tree[i]
                i -= i & -i
            return s

        def add(self, i, x):
            while i <= self.size:
                self.tree[i] += x
                i += i & -i

        def lower_bound(self, w):
            if w <= 0:
                return 0
            x = 0
            k = 1 << (self.size.bit_length() - 1)
            while k:
                if x + k <= self.size and self.tree[x + k] < w:
                    w -= self.tree[x + k]
                    x += k
                k >>= 1
            return x + 1

    N, Q = map(int, input().split())
    C = list(map(int, input().split()))
    query = []
    for q in range(Q):
        query.append(list(map(int, input().split())))
        query[-1].append(q)
    query.sort(key=lambda x: x[1])

    last = [0] * (N+1)
    for i, c in enumerate(C):
        if i > query[0][1]-1:
            break
        last[c] = i+1

    bit = Bit(N)
    for i in range(1, N+1):
        if last[i]:
            bit.add(last[i], 1)
    r_prev = query[0][1]
    ans = [0] * Q
    for l, r, q in query:
        if r > r_prev:
            for i in range(r_prev+1, r+1):
                j = last[C[i-1]]
                if j:
                    bit.add(j, -1)
                last[C[i-1]] = i
                bit.add(i, 1)
        ans[q] = bit.sum(r) - bit.sum(l-1)

    for a in ans:
        print(a)


if __name__ == '__main__':
    main()