#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using Edge = pair<int, int>;
using Graph = vector<vector<Edge>>;
#define REP(i, n) for (int i = 0; i < (n); ++i)
#define SORT(v) sort((v).begin(), (v).end())
#define RSORT(v) sort((v).rbegin(), (v).rend())
const ll MOD = 1000000007;
const ll nmax = 8;
const ll INF = 1e9;
bool graph[nmax][nmax];
vector<vector<ll>> dist = vector<vector<ll>>(nmax, vector<ll>(nmax, INF));
void warshall_floyd(ll n)
{
    for (size_t i = 0; i < n; i++)
    {
        for (size_t j = 0; j < n; j++)
        {
            for (size_t k = 0; k < n; k++)
            {
                dist[j][k] = min(dist[j][k], dist[j][i] + dist[i][k]);
            }
        }
    }
}

class UnionFind
{
public:
    vector<ll> Parent;

    UnionFind(ll N)
    {
        Parent = vector<ll>(N, -1);
    }
    ll find(ll A)
    {
        if (Parent[A] < 0)
            return A;
        return Parent[A] = find(Parent[A]);
    }

    ll size(ll A)
    {
        return -Parent[find(A)];
    }

    bool Union(ll A, ll B)
    {
        A = find(A);
        B = find(B);
        if (A == B)
        {
            return false;
        }
        if (size(A) < size(B))
            swap(A, B);

        Parent[A] += Parent[B];
        Parent[B] = A;

        return true;
    }
};

ll gcd(ll a, ll b)
{
    if (b == 0)
        return a;
    return gcd(b, a % b);
}

ll lcm(ll a, ll b)
{
    ll g = gcd(a, b);
    return a / g * b;
}

ll mulMod(ll a, ll b)
{
    return (((a % MOD) * (b % MOD)) % MOD);
}

ll powMod(ll a, ll p)
{
    if (p == 0)
    {
        return 1;
    }
    else if (p % 2 == 0)
    {
        ll half = powMod(a, p / 2);
        return mulMod(half, half);
    }
    else
    {
        return mulMod(powMod(a, p - 1), a);
    }
}

ll ceil(ll a, ll b)
{
    return (a + b - 1) / b;
}

void solve(long long N, long long W, std::vector<long long> w, std::vector<long long> v)
{

    vector<ll> dp[4];
    ll first = w[0];
    for (int i = 0; i < N; i++)
    {
        dp[w[i] - first].push_back(v[i]);
    }

    for (int i = 0; i < 4; i++)
    {
        RSORT(dp[i]);

        for (int j = 1; j < dp[i].size(); j++)
        {
            dp[i][j] += dp[i][j - 1];
        }
    }

    ll ans = 0;
    for (int a = 0; a <= dp[0].size(); a++)
    {
        for (int b = 0; b <= dp[1].size(); b++)
        {
            for (int c = 0; c <= dp[2].size(); c++)
            {
                for (int d = 0; d <= dp[3].size(); d++)
                {
                    if (N < a + b + c + d)
                    {
                        continue;
                    }
                    if (a * first + b * (first + 1) + c * (first + 2) + d * (first + 3) > W)
                    {
                        continue;
                    }
                    ll value = 0;

                    if (a != 0)
                    {
                        value += dp[0][a - 1];
                    }
                    if (b != 0)
                    {
                        value += dp[1][b - 1];
                    }
                    if (c != 0)
                    {
                        value += dp[2][c - 1];
                    }
                    if (d != 0)
                    {
                        value += dp[3][d - 1];
                    }
                    ans = max(ans, value);
                }
            }
        }
    }
    cout << ans << endl;
}

int main()
{
    long long N;
    scanf("%lld", &N);
    long long W;
    scanf("%lld", &W);
    std::vector<long long> w(N);
    std::vector<long long> v(N);
    for (int i = 0; i < N; i++)
    {
        scanf("%lld", &w[i]);
        scanf("%lld", &v[i]);
    }
    solve(N, W, std::move(w), std::move(v));
    return 0;
}


Measured memory_bytes: 256