## https://yukicoder.me/problems/no/149


def main():
    Aw, Ab = map(int, input().split())
    Bw, Bb = map(int, input().split())
    C, D = map(int, input().split())

    d = max(0, C - Ab)
    
    answer = Aw - d + (min(Bw + d, D))
    print(answer)





if __name__ == "__main__":
    main()