def quick_sort(nums,l,r):
    if l>=r:
        return

    i=l-1
    j=r+1

    x=nums[(l+r)>>1]

    while i<j:

        while True:
            i+=1
            if nums[i]>=x:
                break

        while True:
            j-=1
            if nums[j]<=x:
                break

        if i<j:
            temp = nums[i]
            nums[i]=nums[j]
            nums[j]=temp

    quick_sort(nums,l,j)
    quick_sort(nums,j+1,r)

if __name__=="__main__":
    n=int(input())
    nums=[int(x) for x in input().split()]

    quick_sort(nums,0,n-1)

    target = nums[n//2]


    res=0
    for i in range(0,n):
        res+=abs(target - nums[i])

    print(res)