def main():
    c, d = input().split()
    c = float(c)
    d = float(d)
    b = (21*d - 7*c)/13
    a = (28 * d - 20 * b)/7
    if 0 <= a and 0 <= b:
        print(1000*a+2000*b)
    elif a < 0:
        print(7000*c)
    else:
        print(4000*d)





if __name__ == "__main__":
    import sys
    import os
    if len(sys.argv) > 1:
        if sys.argv[1] == "-d":
            filename = "input1.txt"
            fd = os.open(filename, os.O_RDONLY)
            os.dup2(fd, sys.stdin.fileno())
            main()
    else:
        main()