#include <bits/stdc++.h>
using namespace std;

int main() {
	//freopen("test.in" , "r" ,stdin);

	double a;
	double b;
	double distance[1024];
	double speed[1024];
	double max = 100;

	while(cin >>a , cin >>b){
		//cout <<a << " " << b << endl;
		double small;
		double infinity;
		double old;


		for(int i=0;i<a;i++){
			cin >> distance[i];
			cin >> speed[i];
		//cout << "C : " << c[i] << "     ";
		//cout << "D : " << d[i] << endl;
			small = min(old,speed[i]);
			old = speed[i];
		//	cout << "SMALL : " << small << endl;
		}

		small = -small;
		infinity = 0x3f3f3f3f;

		for(int j = 0; j < max; j++) {
			double check = (small+infinity)/2;
			double sum = 0;
			for (int k = 0; k < a && sum < b; k++)
				sum += distance[k] / (check + speed[k]);
			if (sum > b){
					small = check;
			}
			else{
					infinity = check;
			}
		}
		cout << fixed <<setprecision(9) << small << endl;
	}

	return 0;
}