import sys
input = sys.stdin.readline

INF = 3 << 59

def solve():
    n, s = map(int, input().split())
    x = list(map(int, input().split()))
    w = list(map(int, input().split()))

    # dp[n][n+1][2]
    # C++: vector dp(n, vector(n+1, array<ll,2>))
    dp = [[[INF, INF] for _ in range(n + 1)] for __ in range(n)]

    # 累積和
    sumw = [0] * (n + 1)
    for i in range(n):
        sumw[i + 1] = sumw[i] + w[i]

    # 初期化
    total = sumw[n]
    for i in range(n):
        base = abs(x[i] - s) * total
        dp[i][i + 1][0] = base
        dp[i][i + 1][1] = base

    # DP 遷移
    for l in range(n - 1, -1, -1):
        for r in range(l + 1, n + 1):
            val = total - sumw[r] + sumw[l]

            if r < n:
                v0 = dp[l][r][0] + val * abs(x[l] - x[r])
                if v0 < dp[l][r + 1][1]:
                    dp[l][r + 1][1] = v0

                v1 = dp[l][r][1] + val * abs(x[r - 1] - x[r])
                if v1 < dp[l][r + 1][1]:
                    dp[l][r + 1][1] = v1

            if l > 0:
                v0 = dp[l][r][0] + val * abs(x[l] - x[l - 1])
                if v0 < dp[l - 1][r][0]:
                    dp[l - 1][r][0] = v0

                v1 = dp[l][r][1] + val * abs(x[r - 1] - x[l - 1])
                if v1 < dp[l - 1][r][0]:
                    dp[l - 1][r][0] = v1

    print(min(dp[0][n][0], dp[0][n][1]))


if __name__ == "__main__":
    solve()