 #include<stdio.h>

int main (void){
  int i,n,S[100000],q,T[100000],count=0,left=0,right,mid;
  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++){
    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;
}