#include<bits/stdc++.h>
using namespace std;
long long a[100005],b[100005],m,n,a1=0,ans;
void qsort(long long l,long long r) {
	long long i,j,mid,p;
	i=l;
	j=r;
	mid=a[(l+r)/2];
	while(i<=j) {
		while(a[i]>mid) i++;
		while(a[j]<mid) j--;
		if(i<=j) {
			p=a[i];
			a[i]=a[j];
			a[j]=p;
			i++;
			j--;
		}
	}
	if(l<j) qsort(l,j);
	if(i<r) qsort(i,r);
}
void qsort1(long long l,long long r) {
	long long i,j,mid,p;
	i=l;
	j=r;
	mid=b[(l+r)/2];
	while(i<=j) {
		while(b[i]>mid) i++;
		while(b[j]<mid) j--;
		if(i<=j) {
			p=b[i];
			b[i]=b[j];
			b[j]=p;
			i++;
			j--;
		}
	}
	if(l<j) qsort1(l,j);
	if(i<r) qsort1(i,r);
}
long long abs1(long long aa,long long bb)
{
	if(aa>bb) return aa-bb;
	return bb-aa;
}
int main() {
	cin>>m>>n;
	for(int i=1; i<=m; i++) cin>>a[i];
	for(int i=1; i<=n; i++) cin>>b[i];
	qsort(1,m);
	qsort1(1,n);
	a1=1;
	for(int i=1; i<=n; i++) {
		while(abs1(a[a1],b[i])>abs1(a[a1+1],b[i])&&a1<m) a1++;
		ans+=abs1(a[a1],b[i]);
	}
	cout<<ans;
	return 0;
}