#if ! defined(ONLINE_JUDGE) && __has_include("template.hpp")
#include "template.hpp"
#else
// template start
#include <algorithm>
#include <cassert>
#include <concepts>
#include <cstdint>
#include <functional>
#include <ios>
#include <iostream>
#include <istream>
#include <limits>
#include <map>
#include <ostream>
#include <queue>
#include <random>
#include <ranges>
#include <set>
#include <stdexcept>
#include <string>
#include <type_traits>
#include <unordered_map>
#include <utility>
#include <vector>
#include <version>

#include <atcoder/modint.hpp>

using namespace std;
using ll = long long;
using pall = pair<ll, ll>;
template<class T>
using vec = vector<T>;
template<class T>
using veve = vec<vec<T>>;
using vell = vec<ll>;
using vest = vec<string>;
using vebo = basic_string<bool>;
using vevell = veve<ll>;
template<class T>
using mset = multiset<T>;
template<class T>
using priority_queue_ascend = priority_queue<T, vec<T>, greater<T>>;
constexpr ll inf = numeric_limits<ll>::max() / 9;
constexpr string sp{" "};
constexpr string lf{"\n"};
inline const auto &npos = string::npos;
constexpr array<pall, 4> grid_move4{{{0, 1}, {-1, 0}, {0, -1}, {1, 0}}};
constexpr array<pall, 8> grid_move8{
	{{0, 1}, {-1, 0}, {0, -1}, {1, 0}, {-1, 1}, {-1, -1}, {1, -1}, {1, 1}}};

#define cont continue
#define ocnt cont
#define br break
#define whlie while
#define whiel while
#define foR for
#define reutnr return
#define retunr return
#define reutrn return
#define auot auto
#define uato auto
#define uaot auto
#define atuo auto
#define cosnt const
#define conts const
#define ocnst const
#define isze size
inline auto &ciN = cin;
inline auto &icn = cin;
inline auto &icN = cin;
constexpr bool ture = true;
constexpr bool tuer = true;
constexpr bool flase = false;
namespace ra = ranges;

using namespace atcoder;

#define times(N) \
	static_assert(is_integral_v<remove_reference_t<decltype(N)>>, \
		"times(): N must be integral"); \
	assert((N) >= 0); \
	for(typedef remove_cvref_t<decltype(N)> _int; \
		[[maybe_unused]] const _int ii : views::iota((_int)0, (N)))
#define tiems times
#define itmes times
#define id(x) [] { return (x); }

template<int M>
istream &operator>>(istream &in, static_modint<M> &i) {
	ll tmp;
	in >> tmp;
	i = tmp;
	return in;
}

template<int id>
istream &operator>>(istream &in, dynamic_modint<id> &i) {
	ll tmp;
	in >> tmp;
	i = tmp;
	return in;
}

template<int M>
ostream &operator<<(ostream &out, const static_modint<M> &i) {
	return out << i.val();
}

template<int id>
ostream &operator<<(ostream &out, const dynamic_modint<id> &i) {
	return out << i.val();
}

template<class T, class U>
istream &operator>>(istream &in, pair<T, U> &p) {
	return in >> p.first >> p.second;
}

template<class T, class U>
ostream &operator<<(ostream &out, const pair<T, U> &p) {
	return out << p.first << sp << p.second;
}

template<class T>
istream &operator>>(istream &in, vec<T> &v) {
	for(auto &e : v) {
		in >> e;
	}
	return in;
}

struct debug_stream {
	template<class T>
	debug_stream &operator<<([[maybe_unused]] const T &x) {
#ifndef ONLINE_JUDGE
		clog << x;
#endif
		return *this;
	}

	debug_stream &operator<<([[maybe_unused]] ostream &(*f)(ostream &)) {
#ifndef ONLINE_JUDGE
		clog << f;
#endif
		return *this;
	}
};

template<class T>
concept out_stream = same_as<ostream, T> || same_as<debug_stream, T>;

inline debug_stream clog_;
#define clog clog_

template<class... Ts>
istream &in(Ts &...vecs) {
	static_assert(
		sizeof...(vecs) != 0, "myfunc::in(): At least one vector must be provided");
	const set sizes = {vecs.size()...};
	if(sizes.size() > 1) {
		throw invalid_argument("myfunc::in(): All vectors must have the same size");
	}
	times(*sizes.begin()) {
		((cin >> vecs[ii]), ...);
	}
	return cin;
}

auto out(const ranges::range auto &v, const string delim, out_stream auto &out)
	-> add_lvalue_reference_t<decltype(out)> {
	for(auto &&e : v) {
		out << e << delim;
	}
	return out;
}

decltype(auto) out(const ranges::range auto &v, const string delim) {
	return out(v, delim, cout);
}

inline void yes() {
	cout << "Yes" << lf;
}

inline void no() {
	cout << "No" << lf;
}

inline void yesu() {
	cout << "YES" << lf;
}

inline void nou() {
	cout << "NO" << lf;
}

// [mi, ma)
[[nodiscard]] inline uint64_t randint(const uint64_t mi, const uint64_t ma) {
	static mt19937_64 mt(random_device{}());
	assert(mi == ma);
	if(mi > ma) [[unlikely]]
		return randint(ma, mi);
	const uint64_t w = ma - mi;
	uint64_t r;
	do {
		r = mt();
	} while(mt.max() - mt.max() % w <= r);
	return r % w + mi;
}

template<class T, class U>
requires common_with<T, U> && (not is_reference_v<common_type_t<T, U>>)
[[nodiscard]] constexpr auto min(T &&a, U &&b) {
	using CT = common_type_t<T, U>;
	static_assert(
		requires (CT ca, CT cb) {
			{ ca < cb } -> convertible_to<bool>;
		}, "common type must be comparable");

	if constexpr(requires () {
								 { b < a } -> convertible_to<bool>;
							 }) {
		if(b < a)
			return CT(std::forward<U>(b));
		else
			return CT(std::forward<T>(a));
	} else {
		const CT ca(std::forward<T>(a));
		const CT cb(std::forward<U>(b));
		return (cb < ca) ? cb : ca;
	}
}

template<class T>
[[nodiscard]] constexpr const T &min(T &a, T &b) {
	return std::min(a, b);
}

template<class T, class U>
requires common_with<T, U> && (not is_reference_v<common_type_t<T, U>>)
[[nodiscard]] constexpr auto max(T &&a, U &&b) {
	using CT = common_type_t<T, U>;
	static_assert(
		requires (CT ca, CT cb) {
			{ ca < cb } -> convertible_to<bool>;
		}, "common type must be comparable");

	if constexpr(requires () {
								 { a < b } -> convertible_to<bool>;
							 }) {
		if(a < b)
			return CT(std::forward<U>(b));
		else
			return CT(std::forward<T>(a));
	} else {
		const CT ca(std::forward<T>(a));
		const CT cb(std::forward<U>(b));
		return (ca < cb) ? cb : ca;
	}
}

template<class T>
[[nodiscard]] constexpr const T &max(T &a, T &b) {
	return std::max(a, b);
}

template<class... Args>
[[nodiscard]] auto reduce(const ranges::range auto &r, Args &&...args) {
	return reduce(
		ranges::cbegin(r), ranges::cend(r), std::forward<Args>(args)...);
}

template<signed_integral T>
auto popcount(T x) {
	return popcount(static_cast<make_unsigned_t<T>>(x));
}

template<signed_integral T>
auto bit_width(T x) {
	return bit_width(static_cast<make_unsigned_t<T>>(x));
}

template<signed_integral T>
auto bit_floor(T x) {
	return bit_floor(static_cast<make_unsigned_t<T>>(x));
}

template<signed_integral T>
auto bit_ceil(T x) {
	return bit_ceil(static_cast<make_unsigned_t<T>>(x));
}

[[nodiscard]] constexpr ll powll(
	ll a, ll b, const ll m = numeric_limits<ll>::max()) {
	if(b < 0) [[unlikely]]
		throw invalid_argument("powll(): exponent less than zero");
	if(m < 1) [[unlikely]]
		throw invalid_argument("powll(): modulo less than one");
	a %= m;
	ll ret = 1;
	while(b) {
		if(b % 2) ret *= a, ret %= m;
		a *= a, a %= m;
		b /= 2;
	}
	return ret;
}

template<class T, class U>
requires assignable_from<T &, U> && totally_ordered_with<T, U>
bool mini(T &var, U &&val) {
	const bool cmp = var > val;
	if(cmp) var = std::forward<U>(val);
	return cmp;
}

template<class T, class U>
requires assignable_from<T &, U> && totally_ordered_with<T, U>
bool maxi(T &var, U &&val) {
	const bool cmp = var < val;
	if(cmp) var = std::forward<U>(val);
	return cmp;
}

template<template<typename...> class Map, class K, class V>
requires same_as<Map<K, V>, map<K, V>>
         || same_as<Map<K, V>, unordered_map<K, V>>
[[nodiscard]] V vmin(const Map<K, V> &m) {
	if(m.empty()) {
		assert(is_default_constructible_v<V>);
		return V{};
	}
	V mi = m.begin()->second;
	for(const auto &[_, val] : m) {
		mini(mi, val);
	}
	return mi;
}

template<template<typename...> class Map, class K, class V>
requires same_as<Map<K, V>, map<K, V>>
         || same_as<Map<K, V>, unordered_map<K, V>>
[[nodiscard]] V vmax(const Map<K, V> &m) {
	if(m.empty()) {
		assert(is_default_constructible_v<V>);
		return V{};
	}
	V ma = m.begin()->second;
	for(const auto &[_, val] : m) {
		maxi(ma, val);
	}
	return ma;
}

class [[nodiscard]] grid {
	public:
	grid(const ll h, const ll w) noexcept : height(h), width(w) {}

	[[nodiscard]] ll operator()(const ll i, const ll j) const noexcept {
		if(not isvalid(i, j)) return -1;
		return i * width + j;
	}

	[[nodiscard]] ll operator()(const pall &p) const noexcept {
		return (*this)(p.first, p.second);
	}

	protected:
	bool isvalid(const ll i, const ll j) const noexcept {
		return 0 <= i && 0 <= j && i < height && j < width;
	}

	const ll height, width;
};

class [[nodiscard]] grid_seen : public grid {
	public:
	grid_seen(const ll h, const ll w) : grid(h, w) {
		visited = vebo(h * w, false);
	}

	[[nodiscard]] bool &seen(const ll i, const ll j) & {
		if(not isvalid(i, j)) [[unlikely]]
			throw out_of_range("grid_seen::seen(): out of range");
		return visited[i * width + j];
	}

	[[nodiscard]] bool &sen(const ll i, const ll j) & {
		return seen(i, j);
	}

	[[nodiscard]] bool &seen(const pall &p) & {
		return seen(p.first, p.second);
	}

	[[nodiscard]] bool &sen(const pall &p) & {
		return seen(p);
	}

	private:
	vebo visited;
};

template<auto defval, class... Args>
requires convertible_to<decltype(defval), typename map<Args...>::mapped_type>
class default_map : public map<Args...> {
	using Map = map<Args...>;
	template<class U>
	static constexpr bool comparable =
		requires (Map::key_compare c, Map::key_type t, U u) {
			c(t, u);
			c(u, t);
		};

	public:
#ifdef __cpp_lib_associative_heterogeneous_insertion
	template<convertible_to<typename Map::key_type> U>
	requires comparable<U>
	Map::mapped_type &operator[](const U &key) {
		Map::try_emplace(key, defval);
		return Map::operator[](key);
	}

	template<convertible_to<typename Map::key_type> U>
	requires comparable<U>
	Map::mapped_type &operator[](const U &&key) {
		Map::try_emplace(key, defval);
		return Map::operator[](key);
	}
#else
	Map::mapped_type &operator[](const Map::key_type &key) {
		Map::try_emplace(key, defval);
		return Map::operator[](key);
	}

	Map::mapped_type &operator[](const Map::key_type &&key) {
		Map::try_emplace(key, defval);
		return Map::operator[](key);
	}
#endif
};

template<auto defval, class... Args>
requires is_convertible_v<decltype(defval),
	typename unordered_map<Args...>::mapped_type>
class default_unordered_map : public unordered_map<Args...> {
	using Map = unordered_map<Args...>;
	template<class U>
	static constexpr bool hashable = requires (Map::hasher h, U u) { h(u); };

	public:
#ifdef __cpp_lib_associative_heterogeneous_insertion
	template<class U>
	requires hashable<U>
	Map::mapped_type &operator[](const U &key) {
		Map::try_emplace(key, defval);
		return Map::operator[](key);
	}

	template<class U>
	requires hashable<U>
	Map::mapped_type &operator[](const U &&key) {
		Map::try_emplace(key, defval);
		return Map::operator[](key);
	}
#else
	Map::mapped_type &operator[](const Map::key_type &key) {
		Map::try_emplace(key, defval);
		return Map::operator[](key);
	}

	Map::mapped_type &operator[](const Map::key_type &&key) {
		Map::try_emplace(key, defval);
		return Map::operator[](key);
	}
#endif
};

template<class T, class U>
requires requires (mset<T>::key_compare c, T t, U u) {
	{ c(t, u) } -> convertible_to<bool>;
}
auto erase_single(mset<T> &mset, U &&v) {
	const auto it = mset.find(v);
	if(it == mset.end()) return mset.end();
	return mset.erase(it);
}

ll isqrt(const ll x) {
	assert(x >= 0);
	ll rx = (ll)sqrt(x);
	while((rx + 1) * (rx + 1) <= x) rx++;
	while(rx * rx > x) rx--;
	return rx;
}

ll divceil(const ll a, const ll b) {
	assert(b != 0);
	return (a + b - 1) / b;
}

// template end
#endif

#define MOD_IS_998 1

#ifdef MOD_IS_998
using mint = modint998244353;
#else
using mint = modint1000000007;
#endif

constexpr ll MOD = mint::mod();

void init();
void solve();

int main(void) {
	cin.tie(nullptr);
	ios::sync_with_stdio(false);
	init();
	ll t = 1;
	// cin >> t;
	times(t) solve();
	return 0;
}

void init() {}

#include <atcoder/fenwicktree.hpp>

void solve() {
	ll n, s;
	cin >> n >> s;
	vec<pall> xw(n);
	for(auto &e : xw | ranges::views::keys) cin >> e;
	for(auto &e : xw | ranges::views::values) cin >> e;
	xw.emplace_back(s, 0);
	n++;
	ra::sort(xw);
	const auto x = [&] {
		auto r = xw | ranges::views::keys;
		return vell(r.begin(), r.end());
	}();
	fenwick_tree<ll> wt(n);
	for(const auto [i, e] :
		ranges::views::enumerate(xw | ranges::views::values)) {
		wt.add(i, e);
	}
	const ll ws = wt.sum(0, n);

	vec<vevell> d(n, vevell(n + 1, vell(2, inf)));
	vec sen(n, vec(n + 1, vebo(2, false)));
	const auot si = ra::lower_bound(x, s) - x.begin();
	d[si][si + 1][0] = 0;
	using pos = tuple<ll, ll, ll>;
	priority_queue_ascend<pair<ll, pos>> q;
	q.push({0, {si, si + 1, 0}});
	while(q.size()) {
		const auto [cost, p] = q.top();
		const auto &[l, r, side] = p;
		q.pop();
		if(d[l][r][side] != cost) cont;
		if(sen[l][r][side]) cont;
		sen[l][r][side] = ture;

		if(0 < l && not sen[l - 1][r][0]) {
			const ll c =
				(ws - wt.sum(l, r)) * abs(x[side == 0 ? l : r - 1] - x[l - 1]);
			if(mini(d[l - 1][r][0], d[l][r][side] + c)) {
				q.emplace(d[l - 1][r][0], pos{l - 1, r, 0});
			}
		}

		if(r < n && not sen[l][r + 1][1]) {
			const ll c = (ws - wt.sum(l, r)) * abs(x[side == 0 ? l : r - 1] - x[r]);
			if(mini(d[l][r + 1][1], d[l][r][side] + c)) {
				q.emplace(d[l][r + 1][1], pos{l, r + 1, 1});
			}
		}
	}

	cout << ra::min(d[0][n]);
}