#include <stdio.h>
#include <math.h>
#include <stdlib.h>
int cmp(const void* a,const void* b){
	return *(int*)a-*(int*)b;
}
int min(int a,int b){
	if(a>b) return b;
	else return a;
}
int main(){
	int m,n;
	scanf("%d%d",&m,&n);
	int a[m],b[n];
	for(int i=0;i<m;i++){
		scanf("%d",&a[i]);
	}
	for(int i=0;i<n;i++){
		scanf("%d",&b[i]);
	}
	qsort(b,n,sizeof(int),cmp);
	qsort(a,m,sizeof(int),cmp);
	
	int sum=0;
	for(int i=0;i<n;i++){
		int left=0,right=m-1,mid=(left+right)/2;
		while(1){
		
		if(a[left]-b[i]>=0) {
			sum+=abs(a[left]-b[i]);
			break;
		}
		else if(a[right]-b[i]<=0) {
			sum+=abs(a[right]-b[i]);
			break;	
		}
		else if(a[mid]-b[i]>0) right=mid;
		else if(a[mid]-b[i]<0) left=mid;
		if(left+1==right) {
			sum+=min(abs(a[left]-b[i]),abs(a[right]-b[i])); 
				break;
			}
		mid=(left+right)/2;
		}
	}
	printf("%d",sum);
	return 0; 
}