#include<iostream>

#include<cstdio>

#include<cstring>

#include<algorithm>

using namespace std;

#define ll long long

#define ls l,m,rt<<1

#define rs m+1,r,rt<<1|1

const int maxn=;

const ll inf=1e15;

ll value1[maxn<<],value2[maxn<<];

void pushup(int rt)

{

    value1[rt]=max(value1[rt<<],value1[rt<<|]);

    value2[rt]=min(value2[rt<<],value2[rt<<|]);

}

void btree(int l,int r,int rt)

{

    if(l==r)

    {

        scanf("%lld",&value1[rt]);

        value2[rt]=value1[rt];

        return ;

    }

    int m=(l+r)>>;

    btree(ls);

    btree(rs);

    pushup(rt);

}

ll query1(int L,int R,int l,int r,int rt)

{

    if(L<=l&&r<=R)return value1[rt];

    int m=(l+r)>>;

    ll ans=;

    if(L<=m)ans=max(ans,query1(L,R,ls));

    if(R>m)ans=max(ans,query1(L,R,rs));

    return ans;

}

ll query2(int L,int R,int l,int r,int rt)

{

    if(L<=l&&r<=R)return value2[rt];

    int m=(l+r)>>;

    ll ans=inf;

    if(L<=m)ans=min(ans,query2(L,R,ls));

    if(R>m)ans=min(ans,query2(L,R,rs));

    return ans;

}

int main()

{

    int n,m;

    while(~scanf("%d%d",&n,&m)){

        btree(,n,);

        while(m--){

            int l,r;

            scanf("%d%d",&l,&r);

            printf("%lld\n",query1(l,r,,n,)-query2(l,r,,n,));

        }

    }

}