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

points = []
points.append((0, min(7 * c / 2, 7 * d / 5)))
points.append((min(4 * c / 3, 4 * d), 0))
points.append((20 * c / 13 - 8 * d / 13, - 7 * c / 13 + 21 * d / 13))

ans = 0.0
for x, y in points:
  if x < 0 or y < 0:
    continue
  ans = max(ans, 1000 * x + 2000 * y)

print(ans)