#include<stdio.h>

int A[1000000], n;

int binarySearch(int key) {
    int left = 0, right = n, 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;
}