#include <string.h>

#include <algorithm>

#include <stdio.h>

#include <math.h>

#include <queue>

using namespace std;

const int maxn =  1e5+  ;

const int inf =    0x3f3f3f3f;

struct node{

    int l,r;

    int add;

    int sum;

    int mx;

    int mn;

}tree[maxn<<];

int kase=;

int n,m,t;

int a,b,c;

int val = ;

int ans = ;

int mx,mn;

void pushup(int k)

{

    //tree[k].sum = tree[k<<1].sum+tree[k<<1|1].sum;

    tree[k].mx = max(tree[k<<].mx,tree[k<<|].mx);

    tree[k].mn = min(tree[k<<].mn,tree[k<<|].mn);

}

void build(int l,int r,int k)

{

    tree[k].l = l;  tree[k].r = r;

    if(l == r){scanf("%d",&tree[k].sum); tree[k].mn = tree[k].mx = tree[k].sum; return; }

    int mid = (l+r)>>;

    build(l,mid,k<<);

    build(mid+,r,k<<|);

    pushup(k);

}

void query(int k)

{

    if(a <= tree[k].l && b >= tree[k].r)

    {

      mx = max(mx,tree[k].mx);

      mn = min(mn,tree[k].mn);

      return ;

    }

    int mid = (tree[k].l+tree[k].r)>>;

    if(a <= mid){ query(k<<);}

    if(b > mid){ query(k<<|);}

}

int main()

{

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

  {

    build(,n,);

    while(m--)

    {

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

      mx = -;

      mn = inf;

      query();

      ans = mx -mn;

      printf("%d\n",ans);

    }

  }

}