### Greedy after mill distance

n, w = map(int, input().split())

mills = sorted((tuple(map(int, input().split())) for _ in range(n)), key=lambda x: x[1])

times = []
for i in range(n):
    # assume we use mills 0, ..., i

    travel_time_for_last_mill = 2 * mills[i][1]
    # How much wheat can we process at the nearer mills while driving to the farthest?
    wheat_at_nearer_mills = sum((travel_time_for_last_mill - 2*t) * p for p, t in mills[:i])
    if w > wheat_at_nearer_mills:
        # If there's wheat left to process, all mills 0..i can now work
        total_processing = sum(p for p, _ in mills[:i+1])
        parallel_time = (w - wheat_at_nearer_mills) / total_processing
        times.append(travel_time_for_last_mill + parallel_time)
    else:
        times.append(travel_time_for_last_mill)

print(min(times))