#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;
        }
        if (key>A[mid]) {
            left = mid+1;
        }
        else if (key<A[mid]) {
            right = mid;
        }
    }
    return 0;  // 探索できなかった場合
}

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;
}
