c, d = map(int, input().split())

ans = 0
if 3 * d >= c:
    b = (3 * d - c) * 7 / 13
    a = (c - b * 2 / 7) * 4 / 3
    if a >= 0:
        ans = 1000 * a + 2000 * b
ans = max(ans, 1000 * min(c * 4 / 3, d * 4))
ans = max(ans, 2000 * min(c * 7 / 2, d * 7 / 5))
print(ans)