#include<bits/stdc++.h>
using namespace std;
int a[1999900],b[1999900];
long long m,n;
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];
    }
    sort(a+1,a+m+1);
    long long ans=0;
    for(int i=1;i<=m;i++){
        int l=0,r=m+1;
        while(l<r){
            long long mid=(l+r)/2;
            if(a[mid]<=b[i]){
                l=mid+1;
            }else{
                r=mid;
            }
        }
        if(b[i]<=a[1]){
            ans+=a[1]-b[i];
        }else{
            ans+=min(abs(a[l-1]-b[i]),abs(a[l]-b[i]));
        }
    }
    cout<<ans<<endl;;
    return 0;
}
/**************************************************************
	Problem: 1899
	User: zengdongxin
	Language: C++
	Result: Wrong Answer
****************************************************************/