#include<bits/stdc++.h>

#define maxn 50005

#define ls (rt<<1)

#define rs (rt<<1|1)

#define mid (l+r>>1)

#define INF 0x3f3f3f3f

using namespace std;

int N,Q;

int arr[maxn];

int mx[maxn<<],mi[maxn<<];

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

{

    if(l==r)

    {

        mx[rt]=mi[rt]=arr[l];

        return;

    }

    Build(ls,l,mid);

    Build(rs,mid+,r);

    mx[rt]=max(mx[ls],mx[rs]);

    mi[rt]=min(mi[ls],mi[rs]);

}

int Max(int rt,int l,int r,int s,int t)

{

    if(s>r||t<l)

        return -INF;

    if(s<=l&&r<=t)

        return mx[rt];

    return max(Max(ls,l,mid,s,t),Max(rs,mid+,r,s,t));

}

int Min(int rt,int l,int r,int s,int t)

{

    if(s>r||t<l)

        return INF;

    if(s<=l&&r<=t)

        return mi[rt];

    return min(Min(ls,l,mid,s,t),Min(rs,mid+,r,s,t));

}

int main()

{

    freopen("lineup.in","r",stdin);

    freopen("lineup.out","w",stdout);

    scanf("%d%d",&N,&Q);

    for(int i=;i<=N;i++)

        scanf("%d",&arr[i]);//读入一波

    Build(,,N);

    while(Q--)

    {

        int l,r;

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

        printf("%d\n",Max(,,N,l,r)-Min(,,N,l,r));

    }

    return ;

}