#include <bits/stdc++.h>

using namespace std;

typedef pair<int, int> pii;
typedef long long ll;
const int N = 2000010, MOD = 1e9 + 7, INF = 0x3f3f3f3f;
int n, m, w[N];


int x[N];
ll s[N];
ll f[1024][1024][2];
int main() {
    scanf("%d%d", &n, &m);
    for (int i = 1; i < n + 1; i++) scanf("%d", x + i);
    for (int i = 1; i < n + 1; i++) scanf("%d", w + i), s[i] = s[i - 1] + w[i];
    for (int i = 1; i < n + 1; i++) f[i][i][0] = f[i][i][1] = abs(m - x[i]) * s[n];
    for (int len = 1; len < n; len++)
        for (int i = 1; i + len <= n; i++) {
            int j = i + len;
            f[i][j][0] = min(f[i + 1][j][0] + (s[n] - (s[j] - s[i])) * (x[i + 1] - x[i]), f[i + 1][j][1] + (s[n] - (s[j] - s[i])) * (x[j] - x[i]));
            f[i][j][1] = min(f[i][j - 1][0] + (s[n] - (s[j - 1] - s[i - 1])) * (x[j] - x[i]), f[i][j - 1][1] + (s[n] - (s[j - 1] - s[i - 1])) * (x[j] - x[j - 1]));
        }
    printf("%lld\n", min(f[1][n][0], f[1][n][1]));
    return 0;
}