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For the daily milking, Farmer John‘s N cows (1 ≤ N ≤ 50,000) always line up in the same order. One day Farmer John decides to organize a game of Ultimate Frisbee with some of the cows. To keep things simple, he will take a contiguous range of cows from the milking lineup to play the game. However, for all the cows to have fun they should not differ too much in height.

Farmer John has made a list of Q (1 ≤ Q ≤ 200,000) potential groups of cows and their heights (1 ≤ height ≤ 1,000,000). For each group, he wants your help to determine the difference in height between the shortest and the tallest cow in the group.

//It is made by ljh2000
#include <iostream>
#include <cstdlib>
#include <cstring>
#include <cstdio>
#include <cmath>
#include <algorithm>
using namespace std;
typedef long long LL;
const int MAXN = 50011;
int n,m,a[MAXN],f[MAXN][17],g[MAXN][17],belong[MAXN];
inline int getint(){
    int w=0,q=0; char c=getchar(); while((c<‘0‘||c>‘9‘) && c!=‘-‘) c=getchar();
    if(c==‘-‘) q=1,c=getchar(); while (c>=‘0‘&&c<=‘9‘) w=w*10+c-‘0‘,c=getchar(); return q?-w:w;
}

inline int querymax(int l,int r){
	int t=belong[r-l+1];
	return max(g[l][t],g[r-(1<<t)+1][t]);
}

inline int querymin(int l,int r){
	int t=belong[r-l+1];
	return min(f[l][t],f[r-(1<<t)+1][t]);
}

inline void work(){
	n=getint(); m=getint(); for(int i=1;i<=n;i++) a[i]=getint(),f[i][0]=a[i],g[i][0]=a[i];
	belong[1]=0; for(int i=2;i<=n;i++) belong[i]=belong[i>>1]+1;

	for(int j=1;j<=16;j++) 
		for(int i=1;i<=n;i++) {
			f[i][j]=f[i][j-1];
			if(i+(1<<(j-1))<=n) f[i][j]=min(f[i][j],f[i+(1<<(j-1))][j-1]);
		}

	for(int j=1;j<=16;j++) 
		for(int i=1;i<=n;i++) {
			g[i][j]=g[i][j-1];
			if(i+(1<<(j-1))<=n) g[i][j]=max(g[i][j],g[i+(1<<(j-1))][j-1]);
		}

	int l,r;
	while(m--) {
		l=getint(); r=getint();
		printf("%d\n",querymax(l,r)-querymin(l,r));		
	}
}

int main()
{
    work();
    return 0;
}