#include <bits/stdc++.h>
#define ll long long
#define INF 1000000005
#define MOD 1000000007
#define EPS 1e-10
#define rep(i,n) for(int i=0;i<(int)(n);++i)
#define rrep(i,n) for(int i=(int)(n)-1;i>=0;--i)
#define srep(i,s,t) for(int i=(int)(s);i<(int)(t);++i)
#define each(a,b) for(auto& (a): (b))
#define all(v) (v).begin(),(v).end()
#define len(v) (int)(v).size()
#define zip(v) sort(all(v)),v.erase(unique(all(v)),v.end())
#define cmx(x,y) x=max(x,y)
#define cmn(x,y) x=min(x,y)
#define fi first
#define se second
#define pb push_back
#define show(x) cout<<#x<<" = "<<(x)<<endl
#define spair(p) cout<<#p<<": "<<p.fi<<" "<<p.se<<endl
#define sar(a,n) cout<<#a<<":";rep(pachico,n)cout<<" "<<a[pachico];cout<<endl
#define svec(v) cout<<#v<<":";rep(pachico,v.size())cout<<" "<<v[pachico];cout<<endl
#define svecp(v) cout<<#v<<":";each(pachico,v)cout<<" {"<<pachico.first<<":"<<pachico.second<<"}";cout<<endl
#define sset(s) cout<<#s<<":";each(pachico,s)cout<<" "<<pachico;cout<<endl
#define smap(m) cout<<#m<<":";each(pachico,m)cout<<" {"<<pachico.first<<":"<<pachico.second<<"}";cout<<endl

using namespace std;

typedef pair<int,int> P;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<double> vd;
typedef vector<P> vp;
typedef vector<string> vs;

const int MAX_N = 100005;

void dfs(const int n, const long long W, const long long value, const long long weight, long long& opt,
        const int index, const vector<long long>& rsumw, const vector<long long>& rminw, const vector<pair<long long,long long> >& vec)
{
    if(index == n){
        opt = max(opt, value);
        return;
    }
    if(rsumw[index] <= W - weight){
        long long tvalue = value;
        for(int i = index; i < n; ++i){
            tvalue += vec[i].first;
        }
        opt = max(opt, tvalue);
        return;
    }
    if(rminw[index] > W - weight) return;
    //使う
    if(weight + vec[index].second <= W){
        opt = max(opt, value + vec[index].first);
        long long tweight = weight + vec[index].second, tvalue = value + vec[index].first;
        for(int i = index + 1; i < n; ++i){
            if(tweight + vec[i].second <= W){
                tweight += vec[i].second, tvalue += vec[i].first;
            }else{
                if(rminw[i] <= W - tweight) tvalue += (__int128)vec[i].first * (W - tweight) / vec[i].second;
                break;
            }
        }
        if(opt < tvalue){
            dfs(n, W, value + vec[index].first, weight + vec[index].second, opt, index + 1, rsumw, rminw, vec);
        }
    }
    //使わない
    long long tweight = weight, tvalue = value;
    for(int i = index + 1; i < n; ++i){
        if(tweight + vec[i].second <= W){
            tweight += vec[i].second, tvalue += vec[i].first;
        }else{
            if(rminw[i] <= W - tweight) tvalue += (__int128)vec[i].first * (W - tweight) / vec[i].second;
            break;
        }
    }
    if(opt < tvalue){
        dfs(n, W, value, weight, opt, index + 1, rsumw, rminw, vec);
    }
}
//vec には(価値, 重さ)の順でソートした商品の列を詰める
long long solve(int n, long long W, vector<pair<long long,long long> >& vec)
{
    sort(vec.begin(), vec.end(), [&](const pair<long long, long long>& a, const pair<long long, long long>& b){
        const __int128 diff = a.first * b.second - a.second * b.first;
        return (diff == 0) ? (a.second < b.second) : (diff > 0);
    });
    vector<long long> rsumw(n + 1, 0), rminw(n + 1, numeric_limits<long long>::max());
    for(int i = n - 1; i >= 0; --i){
        rsumw[i] = rsumw[i + 1] + vec[i].second, rminw[i] = min(rminw[i + 1], vec[i].second);
    }
    long long opt = 0;
    dfs(n, W, 0, 0, opt, 0, rsumw, rminw, vec);
    return opt;
}

int main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);
    int n;
    ll W;
    cin >> n >> W;
    vector<pll> vec(n);
    rep(i,n){
        cin >> vec[i].fi >> vec[i].se;
    }
    cout << solve(n,W,vec) << "\n";
    return 0;
}