#include <stdio.h>
#define N 100000
#define Q 50000
int main(){
    int S[N], T[Q], C = 0;
    int left, right, mid, key;
    int n, q, i;
    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++){
        key = T[i];
        left = 0;
        right = n;
        while(left < right){
            mid = (left + right) / 2;
            if(S[mid] == key){
                C++;
                break; }
            else if (key < S[mid]){
                right = mid;
            }
            else left = mid + 1;
        }
    }
    printf("%d\n", C);
    return 0; }

