#!/usr/bin/env python

from sys import stdin

n = int(stdin.readline())
p = [0] * n
for i in xrange(n):
    p[i] = int(stdin.readline())

def chk(s, p, n):
    left = 0
    right = n - 1
    while left <= right:
        mid = (left + right) / 2
        if s > p[mid]:
            left = mid + 1
        elif s < p[mid]:
            right = mid - 1
        else:
            return True
    return False
c = 0
m = int(stdin.readline())
for i in xrange(m):
    s = int(stdin.readline())
    if chk(s, p, n):
        c += 1

print c


The above code is TL8.