#include <cstdio>
#include <utility>
#include <vector>
#include <algorithm>
#include <stack>
#include <stdlib.h>

/***
 * Exponencialni reseni
 */

using namespace std;

vector< pair<int, int> > villages;

int main() {
	int N;
	scanf("%d", &N);

	int position;
	scanf("%d", &position);

	int hats = 0;

	for (int i = 0; i < N; ++i) {
		int index, order;
		scanf("%d%d", &index, &order);
		hats += order;
		villages.push_back(make_pair(index, order));
	}
	sort(villages.begin(), villages.end());

	vector<pair<int, int> > lefts;
	vector<pair<int, int> > rights;

	for (auto it = villages.begin(); it < villages.end(); ++it) {
		if (it->first > position)
			break;
		lefts.push_back(*it);
	}

	for (auto it = villages.end() - 1; it >= villages.begin(); --it) {
		if (it-> first <= position)
			break;
		rights.push_back(*it);
	}

	int best_energy = -1;
	int position_copy;
	int hats_copy;
	int energy;

	vector<pair<int, int> >* sorted_villages[] = {&lefts, &rights};

	for (int i = 0; i < (1 << N); ++i) {
		int i_copy = i;
		position_copy = position;
		hats_copy = hats;
		energy = 0;

		unsigned long remainings[] = {lefts.size(), rights.size()};

		for (int j = 0; j < N; ++j) {
			int dir = i_copy & 1;
			i_copy >>= 1;

			if (!remainings[dir])
				goto end_of_outer_loop;

			pair<int, int>* village = &sorted_villages[dir]->at(remainings[dir]-1);
			--remainings[dir];

			energy += abs(village->first - position_copy) * hats_copy;
			hats_copy -= village->second;
			position_copy = village->first;
		}
		if (best_energy == -1 || energy < best_energy) {
			best_energy = energy;
		}
		end_of_outer_loop:;
	}

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

	return 0;
}