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)

n,q=map(int,input().split())
N=n

data = [0]*(N+1)
def add(k, x):
    while k <= N:
        data[k] += x
        k += k & -k

def get(k):
    s = 0
    while k:
        s += data[k]
        k -= k & -k
    return s

# 二分探索
N0 = 2**(N-1).bit_length()
def lower_bound(x):
    w = i = 0
    k = N0
    while k:
        if i+k <= N and w + data[i+k] <= x:
            w += data[i+k]
            i += k
        k >>= 1
    return i+1

c=[int(i) for i in input().split()]
Q=[]
for i in range(q):
    l,r=map(int,input().split())
    Q.append((l,r,i))
Ans=[0 for i in range(q)]
F=[-1 for i in range(5*10**5+1)]
Q.sort(key=lambda x:x[1])
Q.append((10**6,10**6,10**6))

for i in range(n):
    add(i+1,1)

quen=0
for i in range(n):
    if F[c[i]]>=0:
        add(F[c[i]]+1,-1)
    F[c[i]]=i
    while Q[quen][1]==i+1:
        Ans[Q[quen][2]]=-get(Q[quen][0]-1)+get(Q[quen][1])
        #print(Tre.query(Q[quen][0]-1,Q[quen][1]))
        quen+=1

for ele in Ans:
    print(ele)