#include <stdio.h>
int main()
{
   int i, j, n, S[100000], q, T[50000], key;
   int left, right, mid;
   int count = 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(key = 0; key < q; key++){
        left = 0;
        right = n;
        while (left < right){
            mid = (left + right) / 2;
            if (S[mid] == T[key]){ 
            count++;
            break;
            }else if(T[key] < S[mid]){
            right = mid;
            }else{
            left = mid + 1;
            }
        }
    }
 
    printf("%d\n",count);
     
    return 0;
}