#include <bits/stdc++.h>

using namespace std;

int n,Gmax;
struct obiect
{
    int g,v;
};
obiect a[10001];


void Citire()
{
    int i;
    cin>>n>>Gmax;
    for(i=1;i<=n;i++) cin>>a[i].g>>a[i].v;
}


bool comp(obiect A,obiect B)
{
    return(A.v*B.g>A.g*B.v);
}

void Greedy()
{
    int i;
    double CostMax=0;
    sort(a+1,a+n+1,comp);
    for(i=1;i<=n and Gmax>=a[i].g;i++)
    {
        Gmax-=a[i].g;
        CostMax+=a[i].v;
    }
    if(i<=n and Gmax>0)

        CostMax+=(double)(Gmax*a[i].v)/a[i].g;
    cout<<CostMax<<endl;
}

int main()
{
    Citire();
    Greedy();
    return 0;
}