#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<algorithm>
#include<set>
#include<map>
#include<vector>
#include<queue>
using namespace std;
#define ll long long
#define MAX 220000
inline int read()
{
    int x=0,t=1;char ch=getchar();
    while((ch<'0'||ch>'9')&&ch!='-')ch=getchar();
    if(ch=='-')t=-1,ch=getchar();
    while(ch<='9'&&ch>='0')x=x*10+ch-48,ch=getchar();
    return x*t;
}
int n,m,blk;
struct Query{int l,r,blk,id;}q[MAX];
int cnt[MAX],ans=0;
int Ans[MAX],a[MAX];
int sum[MAX];
bool operator<(Query a,Query b)
{
    if(a.blk!=b.blk)return a.blk<b.blk;
    return a.r<b.r;
}
void work(int l,int w)
{
    if(w==1)
    {
        cnt[a[l]]++;
        if(cnt[a[l]]==1)sum[a[l]/450]++;
    }
    else
    {
        cnt[a[l]]--;
        if(!cnt[a[l]])sum[a[l]/450]--;
    }
}
int calc()
{
    for(int i=0;i<=450;++i)
        if(sum[i]!=450)
            for(int j=0;j<=449;++j)
                if(!cnt[i*450+j])return i*450+j;
}
int main()
{
    n=read();m=read();blk=sqrt(n);
    for(int i=1;i<=n;++i)a[i]=read();
    for(int i=1;i<=m;++i)q[i].l=read(),q[i].r=read(),q[i].id=i,q[i].blk=(q[i].l-1)/blk+1;
    sort(&q[1],&q[m+1]);
    int l=1,r=0;
    for(int i=1;i<=m;++i)
    {
        while(r<q[i].r)work(++r,1);
        while(r>q[i].r)work(r--,-1);
        while(l<q[i].l)work(l++,-1);
        while(l>q[i].l)work(--l,1);
        Ans[q[i].id]=calc();
    }
    for(int i=1;i<=m;++i)
        printf("%d\n",Ans[i]);
    return 0;
}