#include <bits/stdc++.h>

using namespace std;

long long clase[10010], pachete[10010];

ifstream f("clase.in");
ofstream g("clase.out");

int main()
{
  int n, m, st, dr, mij, contor = 0;
  f >> n;
  for(int i = 1; i <= n; i++)
  {
    f >> clase[i];
  }
  f >> m;
  for(int i = 1; i <= m; i++)
  {
    f >> pachete[i];
  }

  for(int i = 1; i <= m; i++)
  {
    st = 1;
    dr = n;

    while(st <= dr)
    {
      mij = (st + dr) / 2;
      if(clase[mij] == pachete[i])
      {
      //  cout << pachete[i] << endl;
        contor++;
        st = dr + 1;
      }
      if(pachete[i] < clase[mij] )
      {
        dr = mij - 1;
      }
      if(pachete[i] > clase[mij]) {
        st = mij + 1;
      }
    }
  }
  g << contor;
}