#include<bits/stdc++.h>
using namespace std;
#include<string.h>

#define vpp vector<pair<int,int>>
#define ll long long int
#define ull unsigned long long
#define ld long double
#define fi(i,a,b) for(ll i=a;i<b;i++)
#define fj(j,a,b) for(ll j=a;j<b;j++)
#define vi vector<int>
#define vl vector<ll>
#define pii pair<int,int>
#define mpi map<int,int>
#define pll pair<ll,ll>
#define mp make_pair
#define mpl map<ll,ll>
#define pb push_back
#define MOD 1000000007
#define ub upper_bound
#define lb lower_bound
#define itr(v) for(auto it:v)
#define all(v) v.begin(),v.end()  
#define w(t)  int t; cin>>t; while(t--)
#define fio ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
ll fast_pow(ll k, ll p)
{
if (p == 0)
        return 1;
 
    ll P = fast_pow(k, p/2);
    P = (P * P) % MOD;
 
    if (p % 2 == 1)
        P = (P * k) % MOD;
 
    return P;
}
ll invmod(ll a,ll m)
{
    return fast_pow(a,m-2);
}

bool isPrime(ll n) 
{ 
   
    if (n <= 1) 
        return false; 
    if (n <= 3) 
        return true; 
  
       if (n % 2 == 0 || n % 3 == 0) 
        return false; 
  
    for (int i = 5; i * i <= n; i = i + 6) 
        if (n % i == 0 || n % (i + 2) == 0) 
            return false; 
  
    return true; 
} 
ll nextPowerOf2(ll n)
{
    n>>=1;
    ll count = 0;

    if (n && !(n & (n - 1)))
        return n;

    while( n != 0)
    {
        n >>= 1;
        count += 1;
    }

    return 1 << count;
}

ll binomialCoeff(ll n, ll k) 
{ 
    ll C[k+1]; 
    memset(C, 0, sizeof(C)); 
    C[0] = 1;
  
    for (ll i = 1; i <= n; i++) 
    {
        for (ll j = min(i, k); j > 0; j--) 
            C[j] = C[j] + C[j-1]; 
    } 
    return C[k]; 
} 


//////////////////////*********CODE***********/////////////////////

  
const int MAX = 500001; 
  
// structure to store queries 
struct Query 
{ 
    int l, r, idx; 
}; 
  
// cmp function to sort queries according to r 
bool cmp(Query x, Query y) 
{ 
    return x.r < y.r; 
} 
  
// updating the bit array 
void update(int idx, int val, int bit[], int n) 
{ 
    for (; idx <= n; idx += idx&-idx) 
        bit[idx] += val; 
} 
  
// querying the bit array 
int query(int idx, int bit[], int n) 
{ 
    int sum = 0; 
    for (; idx>0; idx-=idx&-idx) 
        sum += bit[idx]; 
    return sum; 
} 
  
void answeringQueries(int arr[], int n, Query queries[], int q) 
{ 
    // initialising bit array 
    int bit[n+1]; 
    memset(bit, 0, sizeof(bit)); 
  
    // holds the rightmost index of any number 
    // as numbers of a[i] are less than or equal to 10^6 
    int last_visit[MAX]; 
    memset(last_visit, -1, sizeof(last_visit)); 
  
    // answer for each query 
    int ans[q]; 
    int query_counter = 0; 
    for (int i=0; i<n; i++) 
    { 
        // If last visit is not -1 update -1 at the 
        // idx equal to last_visit[arr[i]] 
        if (last_visit[arr[i]] !=-1) 
            update (last_visit[arr[i]] + 1, -1, bit, n); 
  
        // Setting last_visit[arr[i]] as i and updating 
        // the bit array accordingly 
        last_visit[arr[i]] = i; 
        update(i + 1, 1, bit, n); 
  
        // If i is equal to r of any query  store answer 
        // for that query in ans[] 
        while (query_counter < q && queries[query_counter].r == i) 
        { 
            ans[queries[query_counter].idx] = 
                     query(queries[query_counter].r + 1, bit, n)- 
                     query(queries[query_counter].l, bit, n); 
            query_counter++; 
        } 
    } 
        // print answer for each query 
    for (int i=0; i<q; i++) 
        cout << ans[i] << endl; 
} 
  
// driver code 
int main() 
{ 
    int n,q;
    cin>>n>>q;
    int a[n];
    fi(i,0,n) cin>>a[i];
    Query queries[q]; 
    for(int i=0;i<q;i++){
        int x,y;
        cin>>x>>y;
        x--;
        y--;
        queries[i].l=x;
        queries[i].r=y;
        queries[i].idx=i;
    }
  
    sort(queries, queries+q, cmp); 
    answeringQueries(a, n, queries, q); 
    return 0; 
} 

Measured memory_bytes: 17436