#include <iostream>
#include <fstream>
#include <algorithm>
#include <iomanip>
#include <random>
#include <ctime>
#include <bitset>
#include <map>
#include <set>
#include <unordered_map>
#include <unordered_set>
#include <cmath>
#include <climits>
#include <cstring>
#include <queue>
#include <deque>
#include <list>
#include <stack>

#define pb push_back
#define ff first
#define ss second
#define sqr(x) (x) * (x)
#define cb(x) (x) * (x) * (x)
#define SIZE 101
#define INF 1e18 + 9


using namespace std;

typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

const int inf = 2e9;
const ll linf = 2e18;
const ll mod = 1e9 + 7;

template <typename T>
ostream& operator << (ostream& s, vector<T>& v) {
    for (auto el : v) {
        s << el << " ";
    }
    return s;
}

bool cmp(pii a, pii b) {
    ld xa = a.ff * 1.0 / a.ss;
    ld xb = b.ff * 1.0 / b.ss;
    return xa > xb;
}


int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0), cout.tie(0);
    int n, w; cin >> n >> w;
    vector<pii> a(n);
    for (int i = 0; i < n; i++) {
        cin >> a[i].ff >> a[i].ss;
    }
    sort(a.begin(), a.end(), cmp);
    ld res = 0;
    for (int i = 0; i < n; i++) {
        if (w >= a[i].ss) {
            res += a[i].ff;
            w -= a[i].ss;
        }
        else {
            res += (a[i].ff * 1.0 / a[i].ss) * w;
            w = 0;
        }
    }
    cout << setprecision(10) << res << endl;
    return 0;
}