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蒟蒻的垂死挣扎
// luogu-judger-enable-o2
#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<algorithm>
#include<map>
#include<queue>
#include<set>
#define RG register
#define N 500100
#define ll long long
#define ld long double
using namespace std;
inline ll read(){
RG ll x=0,o=1; RG char ch=getchar();
while((ch<'0'||ch>'9')&&ch!='-') ch=getchar();
if(ch=='-') o=-1,ch=getchar();
while(ch>='0'&&ch<='9') x=x*10+ch-'0',ch=getchar();
return x*o;
}
int len,n,m,a[N],b[N],yyb[N],tot,root[N];
struct mona { int le,ri; int w; } tr[N*20];
inline void Orz(){
sort(yyb+1,yyb+1+n);
len=unique(yyb+1,yyb+1+n)-yyb-1;
for(RG int i=1;i<=n;++i) a[i]=lower_bound(yyb+1,yyb+1+len,a[i])-yyb;
}
inline void Build(RG int l,RG int r,RG int &x,RG int w){
tr[++tot]=tr[x],tr[x=tot].w++;
if(l==r) return ;
RG int mid=(l+r)>>1;
if(w<=mid) Build(l,mid,tr[x].le,w);
else Build(mid+1,r,tr[x].ri,w);
}
inline int Query(RG int l,RG int r,RG int x,RG int y,RG int st){
if(l==r) return l;
RG int sum1=tr[tr[y].le].w-tr[tr[x].le].w,sum2=tr[tr[y].ri].w-tr[tr[x].ri].w;
RG int mid=(l+r)>>1;
if(sum1>st) return Query(l,mid,tr[x].le,tr[y].le,st);
if(sum2>st) return Query(mid+1,r,tr[x].ri,tr[y].ri,st);
return 0;
}
int main(){
n=read(),m=read();
for(RG int i=1;i<=n;++i) a[i]=yyb[i]=read();
Orz();
for(RG int i=1;i<=n;++i){
root[i]=root[i-1],Build(1,len,root[i],a[i]);
}
for(RG int i=1;i<=m;++i){
RG int l=read(),r=read();
printf("%d\n",Query(1,len,root[l-1],root[r],(r-l+1)>>1));
}
}