#ifdef NACHIA
#define _GLIBCXX_DEBUG
#else
#define NDEBUG
#endif
#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
using namespace std;
using ll = long long;
const ll INF = 1ll << 60;
#define REP(i,n) for(ll i=0; i<ll(n); i++)
template <class T> using V = vector<T>;
template <class A, class B> void chmax(A& l, const B& r){ if(l < r) l = r; }
template <class A, class B> void chmin(A& l, const B& r){ if(r < l) l = r; }

void testcase(){
  ll N, S; cin >> N >> S;
  V<ll> X(N); REP(I,N) cin >> X[I];
  V<ll> W(N); REP(i,N) cin >> W[i];
  V<V<ll>> dp(N, V<ll>(N,INF));
  V<ll> sum(N+1); REP(i,N) sum[i+1] = sum[i] + W[i];
  REP(i,N) dp[i][i] = abs(S - X[i]) * sum[N];
  for(ll d=0; d<=N-1; d++){
    for(ll l=0; l+d<N; l++){
      ll r = l + d;
      ll w = sum[N] - sum[r+1] + sum[l];
      if(0 < l) chmin(dp[l-1][r], dp[l][r] + w * (X[l] - X[l-1]));
      if(0 < l) chmin(dp[l-1][r], dp[r][l] + w * (X[r] - X[l-1]));
      if(r+1 < N) chmin(dp[r+1][l], dp[l][r] + w * (X[r+1] - X[l]));
      if(r+1 < N) chmin(dp[r+1][l], dp[r][l] + w * (X[r+1] - X[r]));
    }
  }
  ll ans = min(dp[0][N-1], dp[N-1][0]);
  cout << ans << "\n";
}

int main(){
  cin.tie(0)->sync_with_stdio(0);
  testcase();
  return 0;
}