#include <cstdio>
#include <stack>
#include <set>
#include <iostream>
#include <string>
#include <vector>
#include <queue>
#include <functional>
#include <cstring>
#include <algorithm>
#include <cctype>
#include <string>
#include <map>
#include <cmath>
#define LL long long
#define SZ(x) (int)x.size()
#define Lowbit(x) ((x) & (-x))
#define MP(a, b) make_pair(a, b)
#define MS(arr, num) memset(arr, num, sizeof(arr))
#define PB push_back
#define F first
#define S second
#define ROP freopen("input.txt", "r", stdin);
#define MID(a, b) (a + ((b - a) >> 1))
#define LC rt << 1, l, mid
#define RC rt << 1|1, mid + 1, r
#define LRT rt << 1
#define RRT rt << 1|1
#define BitCount(x) __builtin_popcount(x)
const double PI = acos(-1.0);
const int INF = 0x3f3f3f3f;
using namespace std;
const int MAXN = 50000 + 10;
const int MOD = 1e9 + 7;
const int dir[][2] = { {-1, 0}, {1, 0}, {0, -1}, {0, 1} };
 
typedef pair<int, int> pii;
typedef vector<int>::iterator viti;
typedef vector<pii>::iterator vitii;
 
struct SEGMENTTREE
{
    int vmin, vmax;
}segt[MAXN << 2];
 
void PushUp(int rt)
{
    segt[rt].vmax = max(segt[LRT].vmax, segt[RRT].vmax);
    segt[rt].vmin = min(segt[LRT].vmin, segt[RRT].vmin);
}
 
struct SEGTREE
{
    void build(int rt, int l, int r)
    {
        if (l == r)
        {
            int a;
            scanf("%d", &a);
            segt[rt].vmin = segt[rt].vmax = a;
            return;
        }
        int mid = MID(l, r);
        build(LC); build(RC);
        PushUp(rt);
    }
 
    int queryMax(int rt, int l, int r, int L, int R)
    {
        if (L <= l && r <= R) return segt[rt].vmax;
        int mid = MID(l, r), ans = -1;
        if (L <= mid) ans = queryMax(LC, L, R);
        if (R > mid) ans = max(ans, queryMax(RC, L, R));
        return ans;
    }
 
    int queryMin(int rt, int l, int r, int L, int R)
    {
        if (L <= l && r <= R) return segt[rt].vmin;
        int mid = MID(l, r), ans = INF;
        if (L <= mid) ans = queryMin(LC, L, R);
        if (R > mid) ans = min(ans, queryMin(RC, L, R));
        return ans;
    }
}seg;
 
int main()
{
   // ROP;
    int n, nq, i, j;
    scanf("%d%d", &n, &nq);
    seg.build(1, 1, n);
    while (nq--)
    {
        int a, b;
        scanf("%d%d", &a, &b);
        printf("%d\n", seg.queryMax(1, 1, n, a, b) - seg.queryMin(1, 1, n, a, b));
    }
    return 0;
}