n,k=map(int,raw_input().split())
arr = map(int,raw_input().split())
arr1 = map(int,raw_input().split())
key = k*2;
l = len(arr)
l1 = len(arr1)
mi = 100000000000000000000000;
for k in range(l):
    add=0
    add1=0;
    temp = arr[k]-key;
    temp1 = arr[k]+key;
    for i in range(l):
        if i==k:
            add += temp*arr1[i]
            add1 += temp1*arr1[i]
        else:
            add += arr[i]*arr1[i]
            add1 += arr[i]*arr1[i]
    m = min(add,add1)
    if(mi>m):
        mi = m
print mi    

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

MyA1CjEgMiAtMwotMiAzIC01

3 5
1 2 -3
-2 3 -5