A, B = map(int, input().split())

ans = 10**5
for a in range(0, 201):
    for b in range(0, 201):
        s = a + b
        if s * (10 * A - 5) <= 1000 * a < s * (10 * A + 5):
            if s * (10 * B - 5) <= 1000 * b < s * (10 * B + 5):
                ans = min(ans, s)
print(ans)