#include<iostream>
#include<cstdio>
#include<cmath>
#include<algorithm>
using namespace std;
int a[100100],b[100100];
int m,n;
int main(){
	long long ans=0;
	scanf("%d%d",&m,&n);
	for(int i=1;i<=m;i++) scanf("%d",&a[i]);
	for(int i=1;i<=n;i++) scanf("%d",&b[i]);
	sort(a+1,a+1+n);
	for(int i=1;i<=n;i++){
		int r=m,l=1;
    	int minn=10000;
    	while(l<=r){
     		int mid=(r+l)/2;
    		if(b[i]<a[mid]){
    			r=mid-1;
    			minn=min(abs(a[mid]-b[i]),minn);
    		} 
    		if(b[i]>a[mid]){
    			l=mid+1;
    			minn=min(abs(a[mid]-b[i]),minn);
    		} 
    		if(b[i]==a[mid]){
    			minn=0;
    			break;
    		} 
    	}
        ans+=minn;
	}
	printf("%lld",ans);
	return 0;
}