/**
	author:  shobonvip
	created: 2025.12.26 15:11:03
**/

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

//* ATCODER
#include<atcoder/all>
using namespace atcoder;
typedef modint998244353 mint;
//*/

/* BOOST MULTIPRECISION
#include<boost/multiprecision/cpp_int.hpp>
using namespace boost::multiprecision;
//*/

typedef long long ll;

#define rep(i, s, n) for (int i = (int)(s); i < (int)(n); i++)
#define rrep(i, s, n) for (int i = (int)(n)-1; i >= (int)(s); i--)
#define all(v) v.begin(), v.end()

template <typename T> bool chmin(T &a, const T &b) {
	if (a <= b) return false;
	a = b;
	return true;
}

template <typename T> bool chmax(T &a, const T &b) {
	if (a >= b) return false;
	a = b;
	return true;
}

template <typename T> T max(vector<T> &a){
	assert(!a.empty());
	T ret = a[0];
	for (int i=0; i<(int)a.size(); i++) chmax(ret, a[i]);
	return ret;
}

template <typename T> T min(vector<T> &a){
	assert(!a.empty());
	T ret = a[0];
	for (int i=0; i<(int)a.size(); i++) chmin(ret, a[i]);
	return ret;
}

template <typename T> T sum(vector<T> &a){
	T ret = 0;
	for (int i=0; i<(int)a.size(); i++) ret += a[i];
	return ret;
}

int main(){
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	
	
	ll n, s;
	cin >> n >> s;
	vector<ll> x(n + 1), w(n + 1);
	rep(i,0,n) {
		cin >> x[i];
	}
	rep(i,0,n) {
		cin >> w[i];
	}
	x[n] = s;
	n++;

	

	vector<pair<ll,ll>> p(n);
	rep(i,0,n) p[i] = pair(x[i], w[i]);
	sort(all(p));

	rep(i,0,n) {
		x[i] = p[i].first;
		w[i] = p[i].second;
	}

	vector dp0(n, vector<ll>(n, 2e18));
	vector dp1(n, vector<ll>(n, 2e18));
	rep(i,0,n) {
		if (x[i] == s) {
			dp0[i][i] = 0;
			dp1[i][i] = 0;
			break;
		} 
	}

	vector<ll> wrui(n + 1);
	rep(i,0,n) wrui[i+1] = wrui[i] + w[i]; 

	rrep(l,0,n) {
		rep(r,l+1,n) {
			chmin(dp0[l][r], dp0[l+1][r] + (x[l+1] - x[l  ]) * (wrui[n] - wrui[r+1] + wrui[l+1]));
			chmin(dp0[l][r], dp1[l+1][r] + (x[r  ] - x[l  ]) * (wrui[n] - wrui[r+1] + wrui[l+1]));
			chmin(dp1[l][r], dp1[l][r-1] + (x[r  ] - x[r-1]) * (wrui[n] - wrui[r] + wrui[l]));
			chmin(dp1[l][r], dp0[l][r-1] + (x[r  ] - x[l  ]) * (wrui[n] - wrui[r] + wrui[l]));
		}
	}

	ll ans = min(dp0[0][n-1], dp1[0][n-1]);
	cout << ans << '\n';
}