#pragma GCC optimize("Ofast")
#pragma GCC target ("avx")
#include<bits/stdc++.h>
using namespace::std;
//struct __INIT{__INIT(){cin.tie(0);ios::sync_with_stdio(false);cout<<fixed<<setprecision(15);}} __init;
__attribute__((constructor))
void init(){
	cin.tie(0);
	ios::sync_with_stdio(false);
	cout<<fixed<<setprecision(15);
}
// random_device rd;
// mt19937 mt(rd());
// #include <boost/numeric/interval.hpp>
// #include <boost/numeric/interval/io.hpp>
// #include <boost/intrusive/rbtree.hpp>
// #include <boost/dynamic_bitset.hpp>
// #include <boost/geometry.hpp>
// #include <boost/geometry/geometries/linestring.hpp>
// #include <boost/geometry/geometries/polygon.hpp>
// #include <boost/geometry/geometries/point_xy.hpp>
// #include <boost/math/tools/minima.hpp>
// using boost::math::tools::brent_find_minima;
// #include <boost/multiprecision/cpp_dec_float.hpp>
// #include <boost/multiprecision/cpp_int.hpp>
// namespace mp = boost::multiprecision;
// typedef mp::number<mp::cpp_dec_float<256>> cdouble;
// typedef mp::cpp_int cint;
// #include <boost/unordered_map.hpp>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/priority_queue.hpp>
#include<ext/pb_ds/tag_and_trait.hpp>
template<typename T=long long>using pbds=__gnu_pbds::tree<T,__gnu_pbds::null_type,less<T>,__gnu_pbds::rb_tree_tag,__gnu_pbds::tree_order_statistics_node_update>;
template<typename T=long long>using pbds_map=__gnu_pbds::tree<T,T,less<T>,__gnu_pbds::rb_tree_tag,__gnu_pbds::tree_order_statistics_node_update>;
template<typename T=long long>using pqueue =__gnu_pbds::priority_queue<T, less<T>,__gnu_pbds::rc_binomial_heap_tag>;
typedef long long lint;
typedef long long ll;
typedef long double ldouble;
typedef vector<lint> vec;
typedef vector<vector<lint>> mat;
typedef vector<vector<vector<lint>>> mat3;
typedef vector<double> dvec;
typedef vector<vector<double>> dmat;
typedef vector<vector<vector<double>>> dmat3;
typedef vector<string> svec;
typedef vector<vector<string>> smat;
typedef vector<vector<vector<string>>> smat3;
typedef vector<pair<lint,lint>> pvec;
typedef vector<vector<pair<lint,lint>>> pmat;
typedef vector<vector<vector<pair<lint,lint>>>> pmat3;
#define rep(i, n) for(lint i = 0; i < (lint)(n); i++)
#define irep(i) for(lint i = 0;; i++)
#define irep1(i) for(lint i = 1;; i++)
#define irep2(i) for(lint i = 2;; i++)
#define rrep(i, n) for(lint i = (lint)(n-1); i >-1; i--)
#define rrepi(i,a,b) for(lint i = (lint)(b-1); i >a-1; i--)
#define repi(i,a,b) for(lint i=lint(a);i<lint(b);i++)
#define rep2(i,a,b,c) for(lint i=lint(a);i>lint(b);i+=c)
#define all(x) (x).begin(),(x).end()
#define PI 3.141592653589793
#define dist(x1,y1,x2,y2) (pow(pow(x2-x1,2)+pow(y2-y1,2),0.5))
//#define input(a,n) lint n;cin>>n;vector<lint>a(n);rep(i,n)cin>>a[i];
#define SUM(v) accumulate(all(v),0LL)
#define INF (1LL<<60)
#define IINF (1<<30)
#define EPS (1e-10)
#define LINF 9223372036854775807
//#define MOD 998244353LL
#define MOD 1000000007LL
#define endl "\n"
//struct in{template<class T>operator T(){T t;cin>>t;return t;}};
template<typename T>inline void numout(T t){bool f=0;for(auto i:t){cout<<(f?" ":"")<<i<INF/2?i:"INF";f=1;}cout<<endl;}
template<typename T>inline void numout2(T t){for(auto i:t)numout(i);}
template<typename T>inline void output(T t){bool f=0;for(auto i:t){cout<<(f?" ":"")<<i;f=1;}cout<<endl;}
template<typename T>inline void output2(T t){for(auto i:t)output(i);}
template<typename T>inline void _output(T t){bool f=0;for(int i=0;i<t.size();i++){cout<<f?"":" "<<t[i];f=1;}cout<<endl;}
template<typename T>inline void _output2(T t){for(int i=0;i<t.size();i++)output(t[i]);}
auto Y=[&](auto f){return[&](auto... args){return f(f, args...);};};
template<typename T=lint>T in(){return *istream_iterator<T>(cin);}
template<typename T=lint>inline T gcd(T a,T b){return b?gcd(b,a%b):a;}
template<typename T=lint>inline T lcm(T a,T b){return a/gcd(a,b)*b;}
template<typename T>inline T minq(T a,T b){return min(a,b);}
template<typename T>inline T maxq(T a,T b){return max(a,b);}
inline bool chmin(auto& s,const auto& t){bool res=s>t;s=min(s,t);return res;}
inline bool chmax(auto& s,const auto& t){bool res=s<t;s=max(s,t);return res;}
vector<lint> dx={-1,1,0,0,1,1,-1,-1};
vector<lint> dy={0,0,-1,1,1,-1,1,-1};

class mint {
  using u64 = std::uint_fast64_t;
    public:
    u64 a;
    constexpr mint(const u64 x = 0) noexcept : a(x % MOD) {}
    constexpr u64 &value() noexcept { return a; }
    constexpr const u64 &value() const noexcept { return a; }
    constexpr mint operator+(const mint rhs) const noexcept {
        return mint(*this) += rhs;
    }
    constexpr mint operator-(const mint rhs) const noexcept {
        return mint(*this) -= rhs;
    }
    constexpr mint operator*(const mint rhs) const noexcept {
        return mint(*this) *= rhs;
    }
    constexpr mint operator/(const mint rhs) const noexcept {
        return mint(*this) /= rhs;
    }
    constexpr mint &operator+=(const mint rhs) noexcept {
        a += rhs.a;
        if (a >= MOD) {
            a -= MOD;
        }
        return *this;
    }
    constexpr mint &operator-=(const mint rhs) noexcept {
        if (a < rhs.a) {
            a += MOD;
        }
        a -= rhs.a;
        return *this;
    }
    constexpr mint &operator*=(const mint rhs) noexcept {
        a = a * rhs.a % MOD;
        return *this;
    }
    constexpr mint operator++(int n) const noexcept {
        return mint(*this) +=1;
    }
    constexpr mint operator--(int n) const noexcept {
        return mint(*this) -=1;
    }
    constexpr mint &operator/=(mint rhs) noexcept {
        u64 exp = MOD - 2;
        while (exp) {
            if (exp % 2) {
                *this *= rhs;
            }
            rhs *= rhs;
            exp /= 2;
        }
        return *this;
    }
};
ostream& operator<<(ostream& lhs, const mint& rhs) noexcept {
    lhs << rhs.a;
    return lhs;
}
istream& operator>>(istream& lhs, const mint& rhs) noexcept {
    lhs >> rhs.a;
    return lhs;
}
inline mint pow(mint m,lint n){
    if(n==0)return 1;
    else if(n%2==0){
        mint x=pow(m,n/2);
        return x*x;
    }else{
        return m*pow(m,n-1);
    }
}
inline mint fact(lint a){
    return a?fact(a-1)*a:1;
}

class Comb{
    public:
    vector<lint> fac,ifac;
	constexpr static int mx=1e6;
    Comb(){
        fac.resize(mx+1);
        ifac.resize(mx+1);
        fac[0] = 1;
        ifac[0] = 1;
        rep(i,mx){
            fac[i+1] = fac[i]*(i+1) % MOD;
            ifac[i+1] = ifac[i]*mpow(i+1, MOD-2) % MOD;
        }
    }
    lint mpow(lint x, lint n){
        lint ans = 1;
        while(n != 0){
            if(n&1) ans = ans*x % MOD;
            x = x*x % MOD;
            n = n >> 1;
        }
        return ans;
    }
    lint comb(lint a, lint b){
        if(a == 0 && b == 0)return 1;
        if(a < b || a < 0)return 0;
        lint tmp = ifac[a-b]* ifac[b] % MOD;
        return tmp * fac[a] % MOD;
    }
};

// int main(){
// 	lint x,y,z;
// 	cin>>x>>y>>z;
// 	lint s=x+y+z;
// 	Comb c;
// 	mint ans=0;
// 	vector<mint>list(s);
// 	rep(i,s){
// 		list[i]=mint(c.comb(x+i,i))*c.comb(y+i,i)*c.comb(z+i,i);
// 		rep(j,i){
// 			list[i]-=list[j]*c.comb(i+1,j+1);
// 		}
// 		// cout<<list[i]<<endl;
// 		ans+=list[i];
// 	}
// 	cout<<ans<<endl;
// }

int main(){
    lint n,W;
    cin>>n>>W;
    vector<lint> v(n),w(n),sv(n,0),sw(n,0);
    vector<pair<lint,lint>>p(n);
    rep(i,n)cin>>p[i].second>>p[i].first;
    lint ans=0;
    sort(all(p),[](const auto& s,const auto& t){return s.first*t.second>s.second*t.first;});
    rep(i,n)v[i]=p[i].first;
    rep(i,n)w[i]=p[i].second;
    sw[0]=w[0];
    sv[0]=v[0];
    rep(i,n-1)sv[i+1]=sv[i]+v[i+1];
    rep(i,n-1)sw[i+1]=sw[i]+w[i+1];
    function<void (lint,lint,lint)> f = [&](lint i,lint cur_v,lint cur_w) {
        if (W<cur_w) return;
        if (i == n) {
            ans=max(ans,cur_v);
            return;
        }
        lint lr_v = cur_v;
        lint lr_w = cur_w;
        auto itr=upper_bound(sw.begin(),sw.end(),W-cur_w+(i?sw[i-1]:0));
        lint j=itr-sw.begin();
        lr_w+=sw[j-1]-(i?sw[i-1]:0);
        lr_v+=sv[j-1]-(i?sv[i-1]:0);
        if (lr_w==W||j==n) {
            ans=max(ans,lr_v);
            return;
        }
        double lr_ans=lr_v+v[j]*(W-lr_w)/(double)w[j];
        if(lr_ans<=ans)return;
        if(W>=cur_w+w[i])f(i+1,cur_v+v[i],cur_w+w[i]);
        f(i+1,cur_v,cur_w);
    };
    f(0, 0, 0);
    cout<<ans<<endl;
}


Measured memory_bytes: 256