#include<bits/stdc++.h>
using namespace std;

int s[100005],t[100005],sum;

int main(){
    int n,m;
    cin >> m >> n;
    for(int i = 1;i <= m;i++){
        cin >> s[i];
    }
    for(int i = 1;i <= n;i++){
        cin >> t[i];
    }
    sort(s + 1,s + m + 1);
    for(int i = 1;i <= n;i++){
        if(t[i] >= s[m]) sum += t[i] - s[m];
        else if(t[i] <= s[1]) sum += s[1] - t[i];
        else{
            int num = upper_bound(s + 1,s + m + 1,t[i]) - s;
            if(s[num] > t[i]) sum += s[num] - t[i];
        }
    }
    cout << sum << endl;
    return 0;
}