#include <iostream>
#include<iomanip>
#include<algorithm>
using namespace std;
int main()
{
    long long m, n;
    cin >> m >> n;
    long long* sch = new long long[m];
    for (long long i = 0; i < m; i++) {
        cin >> sch[i];
    }
    sort(sch , sch + m);
    unsigned long long ans = 0;
    for (long long i = 0; i < n; i++) {
        long long num;
        cin >> num;
        long long left ;

        long long right = lower_bound(sch , sch + m, num) - sch;
        if (right == 0) {
            ans += sch[right] - num;
            continue;
        }
        else left = right - 1;
        if (sch[left] + sch[right] - num * 2 > 0) {
            ans += num - sch[left];
        }
        else {

            ans += sch[right] - num;
        }
    }
    cout << ans;
}