#include <stdio.h>

int main (void) {
    int s[100000], t[100000];
    int n, q, i, right, left, mid, 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 ( i = 0; i < q; i++ ) {
        left = 0;
        right = n;
        while ( left < right ) {
            mid = ( right + left ) / 2;
            if ( s[mid] == t[i] || s[mid + 1] == t[i] ) {
                count++;
                break;
            }
            else if ( t[i] < s[mid] ) {
                right = mid;
            }
            else {
                    left = mid + 1;
            }
        }
    }
    
    printf ( "%d\n", count);
    return 0;
}
