from bisect import bisect_left
from collections import defaultdict
N,S=map(int,input().split())
X=list(map(int,input().split()))
W=list(map(int,input().split()))
dp=[defaultdict(int) for _ in range(2)]
w=sum(W)
xi=bisect_left(X,S)
l=xi-1
r=xi
dp[1][(l-1,r,X[l],w-W[l])]=w*abs(S-X[l])
dp[1][(l,r+1,X[r],w-W[r])]=w*abs(S-X[r])
i=0
done=0
while not done:
    done=1
    for (l,r,p,w),ans in dp[1-i].items():
        if l>=0 and p>X[l]:
            if (l-1,r,X[l],w-W[l]) in dp[i]:
                dp[i][(l-1,r,X[l],w-W[l])]=min(dp[i][(l-1,r,X[l],w-W[l])],ans+w*abs(p-X[l]))
            else:
                dp[i][(l-1,r,X[l],w-W[l])]=ans+w*abs(p-X[l])
            if w-W[l]>0:done=0
        if r<N and p<X[r]:
            if (l,r+1,X[r],w-W[r]) in dp[i]:
                dp[i][(l,r+1,X[r],w-W[r])]=min(dp[i][(l,r+1,X[r],w-W[r])],ans+w*abs(p-X[r]))
            else:
                dp[i][(l,r+1,X[r],w-W[r])]=ans+w*abs(p-X[r])
            if w-W[l]>0:done=0
    dp[1-i]=defaultdict(int)
    i=1-i
print(min(dp[1-i].values()))