//Let's join Kaede Takagaki Fan Club !!
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
typedef long long ll;
typedef pair<int,int> P;
typedef pair<int,P> P1;
typedef pair<P,P> P2;
#define pu push
#define pb push_back
#define mp make_pair
#define eps 1e-7
#define INF 1000000000
#define fi first
#define sc second
#define rep(i,x) for(int i=0;i<x;i++)
#define repn(i,x) for(int i=1;i<=x;i++)
#define SORT(x) sort(x.begin(),x.end())
#define ERASE(x) x.erase(unique(x.begin(),x.end()),x.end())
#define POSL(x,v) (lower_bound(x.begin(),x.end(),v)-x.begin())
#define POSU(x,v) (upper_bound(x.begin(),x.end(),v)-x.begin())
#define all(x) x.begin(),x.end()
template<class T>
void dmp(T a){
	rep(i,a.size()) cout << a[i] << " ";
	cout << endl;
}
template<class T>
bool chmax(T&a, T b){
	if(a < b){
		a = b;
		return 1;
	}
	return 0;
}
template<class T>
bool chmin(T&a, T b){
	if(a > b){
		a = b;
		return 1;
	}
	return 0;
}
template<class T>
void g(T &a){
	cin >> a;
}
template<class T>
void o(const T &a,bool space=false){
	cout << a << (space?' ':'\n');
}
//ios::sync_with_stdio(false);
const ll mod = 998244353;
template<class T>
void add(T&a,T b){
	a+=b;
	if(a >= mod) a-=mod;
}


int n;
ll v[5005], w[5005], lim;
vector<pair<ll,ll>>item;
ll ret;
void rec(int pt, ll cur, ll val){
	if(pt == item.size()) return;
	ll zan = lim - cur, relax = val;
	
	for(int i=pt;i<item.size();i++){
		if(zan >= item[i].sc){
			zan -= item[i].sc;
			relax += item[i].fi;
		}
		else{
			relax += ((__int128)(zan) * item[i].fi) / item[i].sc;
			break;
		}
	}
	if(relax <= ret) return;
	if(cur + item[pt].sc <= lim){
		chmax(ret, val + item[pt].fi);
		rec(pt+1, cur + item[pt].sc, val + item[pt].fi);
	}
	rec(pt+1, cur, val);
}
int main(){
	ios::sync_with_stdio(false);
	g(n); g(lim);
	rep(i,n){
		cin >> v[i] >> w[i];
		item.pb(mp(v[i], w[i]));
	}
	sort(item.begin(), item.end(), [&](pair<ll,ll>a, pair<ll,ll>b){
		return (__int128)(a.fi) * b.sc > (__int128)(b.fi) * a.sc;
	});
	
	rec(0, 0, 0);
	o(ret);
}