//p1678，emmm我的输出一直是学生分数的累计，我不李姐
#include<bits/stdc++.h>
using namespace std;
const int N=1e6+10;
typedef long long ll;
ll n,m,a[N],x,ans;
ll find(ll l, ll r,ll x)
{
	while(l<=r)
	{
		ll mid=(l+r)/2;
		if(a[mid]>x)
		{
			ans=min(ans,abs(x-a[mid]));
			r=mid-1;
		}
		else
		{
			ans=min(ans,abs(x-a[mid]));
			l=mid+1;
		}
	}
	return ans;
}
void solve()
{
	cin>>n>>m;
	for(int i=1;i<=n;i++)
		cin>>a[i];
	sort(a+1,a+1+n);
	while(m--)
	{
		cin>>x;
		ans+=(1,n,x);
	}
	cout<<ans;
}
signed main()
{
	ios::sync_with_stdio(false);
	cin.tie(NULL),cout.tie(NULL);
	int T=1;
	while(T--)
	{
		solve();
	}
	return 0;
}