#include <set>
#include <map>
#include <list>
#include <queue>
#include <cmath>
#include <time.h>
#include <random>
#include <bitset>
#include <vector>
#include <cstdio>
#include <stdio.h>
#include <iomanip>
#include <assert.h>
#include <stdlib.h>
#include <memory.h>
#include <string.h>
#include <iostream>
#include <algorithm>
#include <unordered_map>

using namespace std;

typedef long long ll;
typedef unsigned long long ull;

#define mk make_pair
#define fi first
#define se second

inline int read(){
	int t = 0,f = 1;
	register char c = getchar();
	while (c < 48 || c > 57) f = (c == '-') ? (-1) : (f),c = getchar();
	while (c >= 48 && c <= 57) t = (t << 1) + (t << 3) + (c ^ 48),c = getchar();
	return f * t;
}

const int N = 1e6 + 10;
int n,q,inl[N],inr[N],ans[N],val[N];

vector<pair<int,int> > qr[N];

void solve(){
	for (int l = n;l >= 1;l--){
		if (inl[l] == 0){
			int ad = 1;
			for (int i = l + 1;i <= n + 1;i++){
				val[i] += ad;
				if (val[i] > inr[i]){
					if (val[i] - ad <= inr[i] && val[i] - ad >= inl[i]) --ad;
				}else if (val[i] >= inl[i]){
					if (val[i] - ad < inl[i]) ++ad;
				}
				if (ad <= 0) break;
			}
		}
		for (auto q : qr[l]){
			ans[q.se] = val[q.fi + 1];
		}
	}
}

int main(){
#ifndef ONLINE_JUDGE
	freopen("in.in","r",stdin);
	// freopen("out.out","w",stdout);
#endif
	n = read(),q = read();
	for (int i = 1;i <= n;i++) inl[i] = read(),inr[i] = read();
	for (int i = 1;i <= q;i++){
		int l = read(),r = read();
		qr[l].emplace_back(mk(r,i));
	}
	solve();
	for (int i = 1;i <= q;i++) printf("%d\n",ans[i]);
	return 0;
}