#include<iostream>
#include<vector>
#include<algorithm>
#include<iomanip>
using namespace std;
struct gold
{
double value;
double weight;
double rate;
};
bool cmp(const gold& t1,const gold& t2)
{
return t1.rate > t2.rate;
}
int main()
{
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int n, t;
double numt = 0; double numv=0;
vector<gold> v;
cin >> n >> t; if (n < 0 || t < 0 || n>100 || t>1000)return 0;
v.resize(n);
for (int i = 0; i < n; i++)
{
cin >> v[i].weight >> v[i].value; if (v[i].value < 1 || v[i].weight < 1 || v[i].value>120)return 0;
v[i].rate = v[i].value / v[i].weight;
}
sort(v.begin(),v.end(),cmp);
int i = 0;
while (numt <= t && i < n)
{
numt += v[i].weight;//可能会大于
numv += v[i].value;
i++;
}
if (numt > t)
{
numv-=(numt - t)* v[i-1].rate;
}
cout << fixed<<setprecision(2)<<numv;
return 0;
}