#include<bits/stdc++.h>
using namespace std;
const int MAXN=200005,M=-1;
int s[4*MAXN+1],m,n,a[MAXN],y,lz[4*MAXN+1],z,q[MAXN*4],x;
void build(int x,int l,int r)
{
	if(l==r)
	{
		s[x]=a[l];
		return;
	}
	int mid=(l+r)/2;
	build(x*2,l,mid);
	build(x*2+1,mid+1,r);
	s[x]=max(s[x*2],s[x*2+1]);
}
void build2(int x,int l,int r)
{
	if(l==r)
	{
		q[x]=a[l];
		return;
	}
	int mid=(l+r)/2;
	build2(x*2,l,mid);
	build2(x*2+1,mid+1,r);
	q[x]=min(q[x*2],q[x*2+1]);
}
int ask2(int l,int r,int x,int lb,int rb)
{
	if(lb<=l&&r<=rb)
	{
		return q[x];
	}
	if(lb>r||rb<l)
	{
		return MAXN;
	}
	int mid=(l+r)/2;
	return min(ask2(l,mid,x*2,lb,rb),ask2(mid+1,r,x*2+1,lb,rb));
}
int ask(int l,int r,int x,int lb,int rb)
{
	if(lb<=l&&r<=rb)
	{
		return s[x];
	}
	if(lb>r||rb<l)
	{
		return M;
	}
	int mid=(l+r)/2;
	return max(ask(l,mid,x*2,lb,rb),ask(mid+1,r,x*2+1,lb,rb));
}
int main(){
	cin>>m>>n;
	for(int i=1;i<=m;i++)
	{
		cin>>a[i];
	}
	build(1,1,m);
	build2(1,1,m);
	for(int i=1;i<=n;i++)
	{
		cin>>x>>y;
		cout<<ask(1,m,1,x,y)-ask2(1,m,1,x,y)<<endl;
	}
	return 0;
}