C,D = map(int,input().split())
if C/D >= 3:
    print(D * 4000)
elif C/D <= 0.4:
    print(C * 7000)
else:
    CA = (15 * C - 6 * D) / 13
    A = 4 * CA / 3
    B = C + D - A
    print(A * 1000 + B * 2000)