#include "bits/stdc++.h"
using namespace std;

#define       forn(i,n)              for(int i=0;i<n;i++)
#define          all(v)              v.begin(), v.end()
#define         rall(v)              v.rbegin(),v.rend()
#define ll long long
#define            pb                push_back
#define          sz(a)               (int)a.size()
#define         fastio               ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define      GR(a,n,m)               vector<vector<int>> a(n, vector<int>(m, 0));
#define cty cout<<"YES\n"
#define ctn cout<<"NO\n"
int n,m;

int ans;

int w[10000], p[10000];

void dfs(int indice, int sum, int g){
    ans = max(ans,sum);
    for(int i = indice;i<n;i++){

        if(w[i] <= g){
              dfs(i+1,sum + p[i],g-w[i]);
        }


    }

}

void solve(){

    cin >> n >> m;

    forn(i,n){

        cin >> w[i] >> p[i];

    }

    forn(i,n){

        if(w[i] <= m){

            dfs(i+1,p[i],m-w[i]);
        }




    }

    cout<<ans;






}

int32_t main()
{
    fastio;
    freopen("rucsac.in","r",stdin);
    freopen("rucsac.out","w",stdout);
    int t = 1;
   // cin >> t;
    while(t--)
    {
        solve();

    }

}