integer::n,d,ans
integer,allocatable,dimension(:)::a,b,c

read *,n
allocate(a(n-1),b(n),c(n))
do i=1,n-1
 read *,a(i)
end do
do i=1,n
 read *,b(i),c(i)
end do

d=0
ans=0
do i=1,n-1
 d=d-b(i)+c(i)
 ans=ans+d*a(i)
end do

print *,ans

end