#include<bits/stdc++.h>
using namespace std;

int a[100010],b[100010],n,m;
int main(){
    cin>>n>>m;
    for(int i=1;i<=n;i++){
        cin>>a[i];
    }
    for(int i=1;i<=m;i++){
        cin>>b[i];
    }
    sort(a+1,a+n+1);
    int ans=0;
    for(int i=1;i<=m;i++){
        int l=0,r=n+1;
        while(l<r){
            int 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;
}