#include <iostream>
long int bin( long int a[], long int k, int low , int high );
long int count = 0;
int main()
    {
           int n,i;
           std:: cin >> n;
           long int *A = new long int[n];
           for( i=0; i<n; ++i ) std::cin >> A[i];

           long int m,j,key;
           std::cin >> m;
           long int *B = new long int[m];
           for ( j=0; j<m; ++j ) std::cin >> B[j];

           for ( j=0; j<m; ++j )
               {      key = B[j];
                      if (bin(A, key, 0, n-1)) ++count;
               }

           std:: cout << count;
           delete [] A;
           delete [] B;
           return 0;
    }
long int bin( long int a[], long int k, int low , int high )
             {
                 int middle;
                 while(low <= high)
                 {
                    middle = low + high;
                    if (k == a[middle]) return a[middle];
                    else if(k < a[middle]) high = middle-1;
                         else low = middle+1;
                 }
             return 0;
             }