#!/usr/bin/env python


def read():
    input()
    wList = map(int, raw_input().split())
    input()
    bList = map(int, raw_input().split())
    return wList, bList


def work((wList, bList)):
    lengColorList = [] # (leng, isWhite)

    for leng in wList:
        lengColorList.append((leng, True))
    
    for leng in bList:
        lengColorList.append((leng, False))

    lengColorList.sort()

    # dp[lastColor][lastLeng]: best height
    dp = [[-1 for j in range(21)] for i in range(2)]
    dp[0][0] = 0
    dp[1][0] = 0
    
    for (leng, isWhite) in lengColorList:
        for lastLeng in range(leng):
            if dp[not isWhite][lastLeng] == -1:
                continue
            dp[isWhite][leng] = max(dp[isWhite][leng], dp[not isWhite][lastLeng] + 1)

    print max(max(dp[0]), max(dp[1]))
    
    
if __name__ == "__main__":
    work(read())