const int N = 4e5;
const int LG = 21;
const long long MOD = 1e9 + 7;
const long long INF = 1e9;

#include <iostream>
#include <vector>
#include <string>
#include <map>
#include <set>
#include <algorithm>
#include <cmath>
#include <time.h>
#include <unordered_set>
#include <bitset>
#include <deque>

using namespace std;

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<ll> vi;

#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 popcount(x) __builtin_popcount(x)
#define popcountll(x) __builtin_popcountll(x)
#define fi first
#define se second
#define re return
#define uniq(x) sort(all(x)); (x).resize(unique(all(x)) - (x).begin())

#ifdef LOCAL
#define dbg(x) cerr << __LINE__ << " " << #x << " " << x << endl
#define ln cerr << __LINE__ << endl
#else
#define dbg(x) void(0)
#define ln void(0)
#endif // LOCAL

int cx[4] = {-1, 0, 1, 0};
int cy[4] = {0, -1, 0, 1};

ll inq(ll x, ll y)
{
    if (!y) re 1 % MOD;
    ll l = inq(x, y / 2);
    if (y % 2) re l * l % MOD * x % MOD;
    re l * l % MOD;
}

ll rev(ll x)
{
    return inq(x, MOD - 2);
}

bool __precomputed_combinatorics = 0;
vector<ll> __fact, __ufact, __rev;

void __precompute_combinatorics()
{
    __precomputed_combinatorics = 1;
    __fact.resize(N);
    __ufact.resize(N);
    __rev.resize(N);
    __rev[1] = 1;
    for (int i = 2; i < N; i++) __rev[i] = MOD - __rev[MOD % i] * (MOD / i) % MOD;
    __fact[0] = 1, __ufact[0] = 1;
    for (int i = 1; i < N; i++) __fact[i] = __fact[i - 1] * i % MOD, __ufact[i] = __ufact[i - 1] * __rev[i] % MOD;
}

ll fact(int x)
{
    if (!__precomputed_combinatorics) __precompute_combinatorics();
    return __fact[x];
}

ll cnk(int n, int k)
{
    if (!__precomputed_combinatorics) __precompute_combinatorics();
    return __fact[n] * __ufact[n - k] % MOD * __ufact[k] % MOD;
}

void __fast_IO()
{
    #ifdef ONLINE_JUDGE
        ios_base::sync_with_stdio(false);
        cin.tie(0);
        cout.tie(0);
    #endif // ONLINE_JUDGE
}

//##**##**##**##**##**##**##**##**##**##**##**##**##**##**##**##**##**##**##**##**
//##**##**##**##**##**##**##**##**##**##**##**##**##**##**##**##**##**##**##**##**

ll n, w, ba;
vector<ll> a[4];
vector<ll> p[4];

signed main()
{
    __fast_IO();
    cin >> n >> w;
    for (int i = 0; i < n; i++)
    {
        int w, v;
        cin >> w >> v;
        if (i == 0) ba = w;
        w -= ba;
        a[w].push_back(v);
    }
    for (int i = 0; i < 4; i++)
    {
        sort(all(a[i]));
        reverse(all(a[i]));
    }
    for (int i = 0; i < 4; i++)
    {
        p[i].push_back(0);
        for (int j = 0; j < a[i].size(); j++)
        {
            p[i].push_back(p[i].back() + a[i][j]);
        }
    }
    ll ans = 0;
    for (int a = 0; a < p[0].size(); a++)
    {
        for (int b = 0; b < p[1].size(); b++)
        {
            for (int c = 0; c < p[2].size(); c++)
            {
                for (int d = 0; d < p[3].size(); d++)
                {
                    if (ba * a + (ba + 1) * b + (ba + 2) * c + (ba + 3) * d <= w) ans = max(ans, p[0][a] + p[1][b] + p[2][c] + p[3][d]);
                }
            }
        }
    }
    cout << ans;
}

/* Note:
Check constants at the beginning of the code.
N is set to 4e5 but be careful in problems with large constant factor.
Check corner cases.
No def int long long for now.
*/


Measured memory_bytes: 256