#include <stdio.h>

int where ( int a[], int n, int b, int c){
  int x = -1;
  for ( int i = b; i < c; ++i ){
    if ( a[i] == n ){
      x = i;
    }
  }
  return x;
}

int main()
{
 int num = 0;
 int s[100000], t[50000];
 int ns, nt, i, a, j, k;

 scanf("%d", &ns);
 scanf("%d", &s[0]);
 j = 1;
 for ( i = 1; i < ns; ++i ){
   scanf("%d", &s[j]);
   if ( s[j] > s[j-1] ) {
     j++;
   }
 }

 scanf("%d", &nt);
 for ( i = 0; i < nt; ++i ){
  scanf("%d", &t[i]);
  a = where( s, t[i], t[i]-1, j);

  if ( a < 0 ){
   a = 0;
  }
  k = a;
  while ( k < j ){
    if ( t[i] == s[k] ){
      num++;
    }
    k++;
    if ( s[k] > t[i] ) {
      break;
    }
  }
 }

 printf("%d\n", num);

 return 0;
}
