#include <iostream>
#include <cstdio>
#include <cstdlib>
using namespace std;
int apple[2010],tt[2010];
bool die[2010];
int main(void)
{
freopen("applea.in","r",stdin);
freopen("applea.out","w",stdout);
int i,j,applenum,ttnum,ttnumsou,tempj;
cin>>applenum>>ttnum;
ttnumsou=ttnum;
for (i=1;i<=applenum;i++)
cin>>apple[i];
for (i=1;i<=ttnum;i++)
{
cin>>tt[i];
if (tt[i]<=0)
{
i--;
ttnum--;
}
}
for (i=1;i<=applenum;i++)
{
tempj=-1;
for (j=1;j<=ttnum;j++)
{
if (!die[j])
{
if (apple[i]>tt[j])
{
if (tempj==-1)
{
tempj=j;
}
else
{
if (tt[tempj]<tt[j])
{
tempj=j;
}
}
}
}
}
die[tempj]=true;
}
for (i=1;i<=ttnum;i++)
if (die[i])
ttnumsou--;
cout<<ttnumsou<<endl;
return(0);
}