#include <iostream>
#include <set>
using namespace std;

int main()
{
    int n,m;
    cin >>n>>m;
    set <int>good;
    multiset<int>real1;
    set <int>real;

    int x;
    for (int i=0 ;i<n ;i++)
    {
        cin >>x;
        good.insert(x);
    }

    for (int i=0 ;i<m;i++)
    {
        cin >>x;
        real.insert(x);
        real1.insert(x);
    }

    if (m<n)
    {
        set <int>::iterator k,c;
        int res=0;
        for (k=good.begin() ;k!=good.end() ;k++)
        {
            c=real.find(*k);
            if (c!=real.end())
            {
                if (*c==*k)
                {
                   res--;
                }
            }

            else
            {
                c=real1.upper_bound(*k);
                if (c!=real1.end())
                {
                    res--;
                    good.erase(*k);
                    real1.erase(c);
                }
            }
        }

        res+=good.size();

        cout <<res<<endl;
    }

    else
    {
        int res=0;
        int g=good.size();
        set <int>::iterator k,c;
        for (k=good.begin() ;k!=good.end() ;k++)
        {
            c=real.find(*k);
            if (c!=real.end())
            {
                res--;
                good.erase(*k);
                real1.erase(real1.find(*k));
            }

            else
            {
                c=real1.upper_bound(*k);
                if (c!=real1.end())
                {
                    res--;
                    good.erase(*k);
                    real1.erase(c);
                }
            }
        }

        res+=g;
        cout <<res<<endl;
    }
    return 0;
}