#include<bits/stdc++.h>
using namespace std;
int a[100000],b[100000];
int main(){
	int s=0,y;
	int max=10000;
	int n,m;
	cin >> n >> m;
	for(int i = 1;i <= n;i++)cin >> a[i];
	sort(a+1,a+n+1);
	for(int j = 1;j <= m;j++)cin >> b[j];
	int left,right,mid;
	for(int i = 1;i <= m;i++){
		left = 1;
		right = n;
		while(left < right-1){
            mid = (left+right)/2;
            if(b[i] >= a[mid])
            left = mid;
            else right = mid;
        }
        if((b[i]-a[left]) < abs(a[right]-b[i])){
        	y = abs(b[i]-a[left]);
        }else y = abs(a[right]-b[i]);
        s += y;
	}
	cout << s;
    return 0;
}

求助~