// Not afraid to dark.

#include <bits/stdc++.h>
using namespace std;

#define inline __inline__ __attribute__ ((always_inline))

#define ll long long

namespace io {
	int pos;
	inline int read (int &p = pos){
		static int v; static char c;
		v = 1, c = getchar (), p = 0;
		while (! isdigit (c)){
			if (c == '-')
				v = - 1;
			c = getchar ();
		}
		while (isdigit (c)){
			p = (p << 1) + (p << 3) + (c - 48);
			c = getchar ();
		}
		return p *= v;
	}
	inline void write (ll x){
		if (x < 0)
			putchar ('-'), x = - x;
		static int sta[65], top;
		top = 0;
		do {
			sta[++ top] = x % 10;
			x /= 10;
		} while (x);
		while (top)
			putchar (sta[top --] + 48);
	}
};

inline void upd (ll &a, ll b){
	(a < b && (a = b));
}

const int N = 5e5, SQ = 750;
const ll inf = 0x3f3f3f3f3f3fll;
int n, m, B;
struct oper {
	int x, y, t;
} op[N + 5], ls[N + 5];
int ca[N + 5], cb[N + 5], gt[N + 5], y[N + 5];
struct query {
	int l, r, i;
} q[N + 5];
ll ans[N + 5], f[SQ + 5][SQ + 5], g[SQ + 5][SQ + 5], sm[N + 5];

int o;
int pr[N + 5], su[N + 5];
int pre[N + 5], s[N + 5];

void dac (int l, int r){
	if (l == r){
		if (ca[l])
			f[l - o][r - o] = op[l].y;
		return ;
	}
	int mid = (l + r) >> 1;
	dac (l, mid), dac (mid + 1, r);
//	for (int i = l;i <= r;++ i)
//		for (int j = i;j <= r;++ j)
//			printf ("(%d %d %lld)\n", i, j, f[i][j]);
//	puts ("");
	sm[mid] = 0;
	for (int i = mid + 1;i <= r;++ i)
		sm[i] = sm[i - 1] + op[i].y;
	pr[l - 1] = l - 1, su[l - 1] = mid;
	for (int i = l, x = l, y = mid + 1;i <= r;++ i){
		if (y > r || (x <= mid && op[x].t < op[y].t))
			ls[i] = op[x ++];
		else
			ls[i] = op[y ++];
		pr[i] = x - 1;
		su[i] = y - 1;
	}
	for (int i = l;i <= r;++ i)
		op[i] = ls[i];
	for (int i = l, j;i <= mid;++ i)
		for (j = i;j <= mid;++ j)
			g[i - o][j - o] = f[i - o][j - o];
	for (int i = mid + 1, j;i <= r;++ i)
		for (j = i;j <= r;++ j)
			g[i - o][j - o] = f[i - o][j - o];
	for (int i = l, j, li, lj, ri, rj;i <= r;++ i)
		for (j = i;j <= r;++ j){
			li = pr[i - 1] + 1, lj = pr[j], ri = su[i - 1] + 1, rj = su[j];
			f[i - o][j - o] = - inf;
			if (cb[mid] - cb[l - 1])
				upd (f[i - o][j - o], g[li - o][lj - o] + sm[rj] - sm[ri - 1]);
			if (cb[r] - cb[mid])
				upd (f[i - o][j - o], g[ri - o][rj - o]);
		}
}

inline void Solve (int l, int r){
	o = l - 1;
	for (int i = l;i <= r;++ i)
		for (int j = i;j <= r;++ j)
			f[i - o][j - o] = - inf;
	dac (l, r);
//	for (int i = l;i <= r;++ i)
//		for (int j = i;j <= r;++ j)
//			printf ("(%d %d %lld)\n", i, j, f[i][j]);
//	puts ("");
	pre[0] = l - 1;
	for (int i = 1;i <= n;++ i){
		pre[i] = pre[i - 1];
		if (op[pre[i] + 1].t <= i && pre[i] < r)
			++ pre[i];
		s[i] = s[i - 1] + (gt[i] > r ? y[i] : 0);
//		printf ("%d %d\n", pre[i], s[i]);
	}
	for (int i = 1, ql, qr;i <= m;++ i){
		ql = pre[q[i].l - 1] + 1, qr = pre[q[i].r];
//		printf ("%lld %lld %lld\n", ans[i], f[ql - o][qr - o], s[q[i].r] - s[q[i].l - 1]);
		if (cb[r] - cb[l - 1])
			upd (ans[i], f[ql - o][qr - o] + s[q[i].r] - s[q[i].l - 1]);
	}
}

signed main (){
	io::read (n), io::read (m);
	B = (int) sqrt (n);
	for (int i = 1;i <= n;++ i)
		io::read (op[i].x), io::read (op[i].y), op[i].t = i, y[i] = op[i].y;
	for (int i = 1;i <= m;++ i)
		io::read (q[i].l), io::read (q[i].r), q[i].i = i, ans[i] = - inf;
	sort (op + 1, op + n + 1, [] (const oper &a, const oper &b){
		return a.x != b.x ? a.x < b.x : a.t < b.t;
	});
	op[n + 1].x = n;
	op[n + 1].y = 0;
	op[n + 1].t = n + 1;
	++ n;
//	for (int i = 1;i <= n;++ i)
//		printf ("%d %d %d\n", op[i].x, op[i].y, op[i].t);
	for (int i = 1;i <= n;++ i)
		gt[op[i].t] = i;
	for (int i = 1;i <= n;++ i)
		ca[i] = (i == 1 || op[i].x != op[i - 1].x), cb[i] = cb[i - 1] + ca[i];
	for (int l = 1, r = B;l <= n;l = r + 1, r = min (l + B - 1, n))
		Solve (l, r);
	for (int i = 1;i <= m;++ i)
		io::write (ans[i]), putchar ('\n');
	return 0;
}