#Include<stdio.h>
int n, S[100000];

int binarySearch(int key){
  int left = 0, middle, right = n;
  
  while(left < right){
    middle = (left + right) / 2;
    printf("left = %d, right = %d, middle = %d", left, right, middle);
    printf(" key = %d, S[%d] = %d\n", key, middle, S[middle]);

    if(key == S[middle])
      return 1;
    if(key > S[middle])        left = middle + 1;
    else if(key < S[middle])   right = middle;
  }
  return 0;
}

int main(){
  int q, T[100000], i, cnt = 0;

  scanf("%d", &n);
  for(i = 0; i < n; i++)
    scanf("%d", &S[i]);

  scanf("%d", &q);
  for(i = 0; i < q; i++)
    scanf("%d", &T[i]);

  for(i = 0; i < q; i++){
    if(S[binarySearch(T[i])]){
      cnt++;
    }
  }

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

  return 0;
}