#include<iostream>

#include<cstdio>

#include<cstring>

#include<algorithm>

#include<cmath>

#define Max(a,b) ((a)>(b)?(a):(b))

#define Min(a,b) ((a)<(b)?(a):(b))

#define Maxn 60010

using namespace std;

int maxnum[Maxn][],minnum[Maxn][],n,Log[Maxn+];

int Log2(int x)

{

    int num=;

    x/=;

    while(x)

    {

        num++;

        x/=;

    }

    return num;

}

void RMQ()

{

    int i,j;

    for(j=;j<;j++)

        for(i=;i<=n;i++)

        if(i+(<<j)-<=n)

        {

            maxnum[i][j]=Max(maxnum[i][j-],maxnum[i+(<<(j-))][j-]);

            minnum[i][j]=Min(minnum[i][j-],minnum[i+(<<(j-))][j-]);

        }

}

int main()

{

    int i,j,q,a,b;

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

        Log[i]=Log2(i);

    while(scanf("%d%d",&n,&q)!=EOF)

    {

        for(i=;i<=n;i++)

        {

            scanf("%d",&a);

            maxnum[i][]=minnum[i][]=a;

        }

        RMQ();

        for(i=;i<=q;i++)

        {

            scanf("%d%d",&a,&b);

            int k=Log[b-a+];

            printf("%d\n",Max(maxnum[a][k],maxnum[b-(<<k)+][k])-Min(minnum[a][k],minnum[b-(<<k)+][k]));

        }

    }

    return ;

}