#include<bits/stdc++.h>
using namespace std;
#define int long long
int n,m,a[100100],x,s;
signed main(){
	cin>>n>>m;
	for(int i=1;i<=n;i++) scanf("%lld",&a[i]);
	sort(a+1,a+1+n);
	int l,r,mid;
	for(int i=1;i<=m;i++) {
		scanf("%d",&x);
		if(x<=a[1]) s=s+a[1]-x;
		else if(x>=a[n]) s=s+x-a[n];
		else{
			l=1,r=n;
			while(l<=r)
			{
				mid=r+l>>1;
				if(x<=a[mid]) r=mid-1;
				else l=mid+1;
			}
			s=s+min(a[l]-x,x-a[l-1]);
		}
	}
	cout<<s;
	return 0;
}