#include<bits/stdc++.h>
using namespace std;
#define int long long
const int N = 1e6+10;
int a[N],b[N];
signed main()
{
	int m,n;
	int sum = 0;
	cin>>m>>n;
	for(int i = 1;i<=m;i++){
		cin>>a[i];
	}
	if(m==1){
		for(int i = 1;i<=n;i++){
			cin>>b[i];
			sum+=abs(a[1]-b[i]);
		}
		cout<<sum<<endl;
		
		return 0;
	}
	sort(a+1,a+1+m);
	for(int i = 1;i<=n;i++){
		cin>>b[i];
		int l = 0,r = n+1;
		while(r-l>1){
			int mid = (l+r)>>1;
			if(a[mid]>b[i]){
				r = mid;
			}else{
				l = mid;
			}
		}
		if(b[i]<=a[1]){
			sum+=(a[1]-b[i]);
		}
		else{
			if(abs(a[r-1]-b[i])>abs(a[r]-b[i])){
				sum += abs(a[r]-b[i]);
			}else{
				sum += abs(a[r-1]-b[i]);
			}
		}
	}
	cout<<sum<<endl;
	
	return 0;
}