#include<stdio.h>

int A[1000000], n;

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;
        if ( key > A[mid] ) left = mid + 1;
        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;
}

