#include <stdio.h>

int A[1000000], n;

/* 二分探索 */
int binarySearch(int key) {
    int left = 0;
    int right = n;
    int mid;

    while (left < right) {
        mid = (left + right) / 2;
        if (key == A[mid]) return (1);      /* keyを発見  */
        
        if (key >  A[mid]) {
            left = mid + 1;  /* 後半を探索 */
        }
        else if (key < A[mid]) {
            right = mid;
        } 
    }
    return (0);
}

int main()
{
    int i, q, k, sum = 0;

    scanf("%d", &n);
    for (i = 0; i < n; i++) {
        scanf("%d", &A[i]);
    }

    scanf("%d", &q);
    for (i = 0; i < q; i++) {
        scanf("%d", &k);
        if (binarySearch(k)) {
            sum++;
        }
    }
    printf("%d\n", sum);

    return (0);
}
