#include <stdio.h>
#define N 100000
#define Q 50000

int main() {

  int i,j,n,q,count=0,left,right,mid;
  int S[N],T[Q];

  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]);
    left = 0;
    right = n;
    while(left<right) {
      mid = (left + right) / 2;
      if(S[mid]==T[i]) {
        count++;
        break;
      } 
      else if(T[i]<S[mid]) right = mid;
      else left	= mid +	1;
    }
  }

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

  return 0;
}