#include<stdio.h>
#include<stdlib.h>
#include<math.h>
#include <bits/stdc++.h>
using namespace std;
int main()
{
    long long int m,n;
    long long int sum=0;
    scanf("%lld %lld",&m,&n);
    long long int i,j;
    long long int v[100010];
    j=0;
    while(j<m) {
        scanf("%lld",&v[j]);
        j++;
    }
    sort(v,v+j);
    for(i=0; i<n; i++) {
        long long int score;
        scanf("%lld",&score);
        long long int l,r,mid;
        l=0;
        r=j-1;
        while(score>v[l]&&score<v[r]&&l<r-1) {
            mid=l+(r-l)/2;
            if(score>v[mid])l=mid;
            else if(score<v[mid])r=mid;
        }
        if(score==v[l]||score==v[r])sum+=0;

        else sum+=min(abs(score-v[l]),abs(score-v[r]));
    }
    printf("%lld",sum);
    return 0;
}