def f(x, y, a):
    return (x > 30) or (y > 40) or (2 * x + 3 * y < a)
for a in range(1, 1000):
    if all(f(x, y, a) == 1 for x in range(1, 1000) for y in range(1, 1000)):
        print(a)
        break