#include<bits/stdc++.h>

int main() {
	using namespace std;
	cin.tie(nullptr)->sync_with_stdio(false);
	int N, T; cin >> N >> T;

	vector<int> D(N), S(N);
	for (int i = 0; i < N; ++i) {
		cin >> D[i] >> S[i];
	} 

	auto check = [&](double C) -> bool {
		double ans = 0.0;
		for (int i = 0; i < N; ++i) {
			ans += 1.0 * D[i] / (S[i] + C);
		}
		return ans <= T;
	};

	double mi = -4e9, ma = 4e9;

	double min_val = -*min_element(S.begin(), S.end());
	mi = max(mi, min_val);
	for (int z = 0; z < 200; ++z) {
		double md = (mi + ma) / 2.0;
		check(md) ? ma = md : mi = md;
	}

	cout << fixed << setprecision(20);
	cout << ma << '\n';
}