## https://yukicoder.me/problems/no/2329


def main():
    C,D = map(int, input().split())

    x = (- (40 / 91)) * ((7 * D / 5) - (7 * C / 2))
    y = - ((21 * x) / 8) + 7 * C / 2

    if x >= 0.0 and y >= 0.0:
        k = x + 2 * y
        print(k * 1000)
    elif y < 0.0:
        x = 4 * D
        y = 0
        k = x + 2 * y
        print(1000 * k)
    else:
        # x < 0.0
        x = 0
        y = 7 * C / 2
        k = x + 2 * y
        print(1000 * k)




if __name__ == "__main__":
    main()