using System;
using System.Collections.Generic;
using System.Linq;
using static System.Console;
using static System.Math;

class MainClass : Scanner
{
    static void Main()
    {
        var (N, W) = ReadTuple<int,int>();
        var wv = new int[N][];
        wv[0] = RInts();
        int firstw = wv[0][0];
        wv[0][0] -= firstw;
        for (int i = 1; i < N; i++)
        {
            wv[i] = RInts();
            wv[i][0] -= firstw;
        }
        var dp = new int[N + 1, 3 * N + 1];
        for (int i = 0; i < N+1; i++)
        {
            for (int j = 0; j < 3*N+1; j++)
            {
                dp[i, j] = -1;
            }
        }
        dp[0, 0] = 0;
        for (int i = 0; i < N; i++)
        {
            var item = wv[i];
            for (int j = N-1; j >= 0; j--)
            {
                for (int k = 3*N; k >= 0; k--)
                {
                    if (dp[j, k] == -1) continue;

                    int nj = j + 1;
                    int nk = k + item[0];
                    dp[nj, nk] = Max(dp[nj, nk], dp[j, k] + item[1]);
                }
            }
        }
        int ans = 0;
        for (int i = 0; i < N+1; i++)
        {
            for (int j = 0; j < 3*N+1; j++)
            {
                if ((long)firstw * i + j > W) break;
                ans = Math.Max(ans,dp[i,j]);
            }
        }
        WriteLine(ans);
    }
}



class Scanner
{
    public static string RString() => Console.ReadLine();
    public static int RInt() => ReadTuple<int>();
    public static long RLong() => ReadTuple<long>();
    public static double RDouble() => ReadTuple<double>();

    public static string[] RStrings() => Console.ReadLine().Split();
    public static int[] RInts() => Array.ConvertAll(Console.ReadLine().Split(), int.Parse);
    public static long[] RLongs() => Array.ConvertAll(Console.ReadLine().Split(), long.Parse);
    public static double[] RDoubles() => Array.ConvertAll(Console.ReadLine().Split(), double.Parse);
    public static int[] RInts(Func<string, int> func) => Console.ReadLine().Split().Select(func).ToArray();
    public static long[] RLongs(Func<string, long> func) => Console.ReadLine().Split().Select(func).ToArray();
    public static double[] RDoubles(Func<string, double> func) => Console.ReadLine().Split().Select(func).ToArray();
    //public static string[] RStrings(Func<string, string> func) => Console.ReadLine().Split().Select(func).ToArray();

    public static T1 ReadTuple<T1>()
    {
        var r = RString();
        var r1 = (T1)Convert.ChangeType(r, typeof(T1));
        return r1;
    }
    public static (T1, T2) ReadTuple<T1, T2>()
    {
        var r = RStrings();
        var r1 = (T1)Convert.ChangeType(r[0], typeof(T1));
        var r2 = (T2)Convert.ChangeType(r[1], typeof(T2));
        return (r1, r2);
    }
    public static (T1, T2, T3) ReadTuple<T1, T2, T3>()
    {
        var r = RStrings();
        var r1 = (T1)Convert.ChangeType(r[0], typeof(T1));
        var r2 = (T2)Convert.ChangeType(r[1], typeof(T2));
        var r3 = (T3)Convert.ChangeType(r[2], typeof(T3));
        return (r1, r2, r3);
    }
    public static (T1, T2, T3, T4) ReadTuple<T1, T2, T3, T4>()
    {
        var r = RStrings();
        var r1 = (T1)Convert.ChangeType(r[0], typeof(T1));
        var r2 = (T2)Convert.ChangeType(r[1], typeof(T2));
        var r3 = (T3)Convert.ChangeType(r[2], typeof(T3));
        var r4 = (T4)Convert.ChangeType(r[3], typeof(T4));
        return (r1, r2, r3, r4);
    }
}


Measured memory_bytes: 27672