ALDS_4_B – 二分探索

n = int(input())
s = list(map(int,input().split()))
q = int(input())
t = list(map(int,input().split()))

def search(x):
    l = 0
    r = n-1
    while l <= r:
        mid = (l+r)//2
        if s[mid] == x:
            return 1
        elif s[mid] < x:
            l = mid + 1
        else:
            r = mid -1
    return 0
            

ans = 0
for i in t:
    ans += search(i)

print(ans)