#include <cassert>
//PXjUXeZStdX
#include <cctype>
#include <cerrno>
#include <cfloat>
#include <ciso646>
#include <climits>
#include <clocale>
#include <cmath>
#include <csetjmp>
#include <csignal>
#include <cstdarg>
#include <cstddef>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <ccomplex>
#include <cfenv>
#include <cinttypes>
#include <cstdbool>
#include <cstdint>
#include <ctgmath>
#include <cwchar>
#include <cwctype>

// C++
#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <typeinfo>
#include <utility>
#include <valarray>
#include <vector>
#include <array>
#include <atomic>
#include <chrono>
#include <condition_variable>
#include <forward_list>
#include <future>
#include <initializer_list>
#include <mutex>
#include <random>
#include <ratio>
#include <regex>
#include <scoped_allocator>
#include <system_error>
#include <thread>
#include <tuple>
#include <typeindex>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>
// #include <boost/foreach.hpp>
// #include <boost/range/algorithm.hpp>
#define rep(i,j,k) for(int i=(int)j;i<(int)k;i++)
#define ll long long
#define Sort(v) sort(all(v))
//#define INF 1e9
#define LINF (1LL<<40)
#define END return 0
#define pb push_back
#define se second
#define fi first
#define pb push_back
#define all(v) (v).begin() , (v).end()
#define MP make_pair
#define int long long
using namespace std;
int day[12]={31,28,31,30,31,30,31,31,30,31,30,31};
// int dx[]={0,1,0,-1};
// int dy[]={1,0,-1,0};
typedef pair<int,int> P;

const long long MOD=1000000007LL;
bool isupper(char c){if('A'<=c&&c<='Z')return 1;return 0;}
bool islower(char c){if('a'<=c&&c<='z')return 1;return 0;}
bool iskaibun(string s){for(int i=0;i<s.size()/2;i++)if(s[i]!=s[s.size()-i-1])return 0;return 1;}
bool isnumber(char c){return ('0'<=c&&c<='9');}
bool isalpha(char c){return (isupper(c)||islower(c));}
template<typename T> 
void print(vector<T> v){
    for(int i=0;i<v.size();i++){
        if(i)cout<<" ";
        cout<<v[i];
    }
    cout<<endl;
}
int INF=1e18;

template<typename T>
void printendl(vector<T> v){
    for(auto date:v)cout<<date<<endl;
}

template<typename T>
void printvv(vector<vector<T>> v){
    for(int i=0;i<v.size();i++){
        for(int j=0;j<v[i].size();j++){
            if(j)cout<<" ";
            cout<<v[i][j];
        }
        cout<<endl;
    }
}
int gcd(int a,int b){
    if(a<b)swap(a,b);
    if(b==0)return a;
    else return gcd(b,a%b);
}

int powl(int n,int p){
    int ret=1;
    for(int i=0;i<p;i++)ret*=n;
    return ret;
}

struct Edge{
    int to,cost;
};

struct S{
    pair<int,int> p;
    int x;
};

int n;
vector<vector<int>> g;
int d[2][100010]={};
int mode=0;

void dfs(int idx,int par){
    if(par!=-1)d[mode][idx]=d[mode][par]+1;
    rep(i,0,g[idx].size()){
        if(par!=g[idx][i])dfs(g[idx][i],idx);
    }
    return;
}

signed main (){
    int n;
    cin>>n;
    int W; cin>>W;
    vector<vector<int>> v(4);
    int sw;
    rep(i,0,n){
        int w,vv; cin>>w>>vv;
        if(i==0){
            sw=w;
            v[0].push_back(vv);
        }
        else v[w-sw].push_back(vv);
    }
    
    rep(i,0,4){
        if(v[i].empty())v[i].push_back(0);
        sort(all(v[i]), greater<int>());
    }

    vector<vector<int>> rui(4);
    rep(i,0,4){
        rui[i].push_back(v[i][0]);
        rep(j,1,v[i].size()){
            rui[i].push_back(rui[i][j-1]+v[i][j]);
        }
    }
    int ans=0;
    rep(i,0,4)if(rui[i].size()!=1 or (rui[i].size()==1 && rui[i][0]!=0))rui[i].insert(rui[i].begin(),0);
    //rep(i,0,4)print(rui[i]);
    rep(x1,0,rui[0].size()){
        rep(x2,0,rui[1].size()){
            rep(x3,0,rui[2].size()){
                rep(x4,0,rui[3].size()){
                    //cout<<x1<<" "<<x2<<" "<<x3<<" "<<x4<<" "<<rui[0][x1]+rui[1][x2]+rui[2][x3]+rui[3][x4]<<endl;
                    int tempw=(x1)*sw+(x2)*(sw+1)+(x3)*(sw+2)+(x4)*(sw+3);
                    if(tempw<=W /*&& x1>0 && x2>0&&x3>0&&x4>0*/)ans=max(ans,rui[0][x1]+rui[1][x2]+rui[2][x3]+rui[3][x4]);
                }
            }
        }
    }
    cout<<ans<<endl;

    





    


}

/*


*/

Measured memory_bytes: 256