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

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    static int[][] NArr(long n) => Enumerable.Repeat(0, (int)n).Select(_ => NList).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var d = NList;
        var (n, v, c) = (d[0], d[1], d[2]);
        var map = NArr(n);
        var dp = Enumerable.Repeat(long.MinValue, v + 1).ToArray();
        dp[0] = 0;
        for (var i = 0; i < n; ++i)
        {
            var ndp = (long[]) dp.Clone();
            for (var j = 0; j < v; ++j) if (j + map[i][0] <= v) ndp[j + map[i][0]] = Math.Max(ndp[j + map[i][0]], dp[j] + map[i][1] + c);
            dp = ndp;
        }
        for (var i = 0; i < n; ++i)
        {
            for (var j = 0; j < v; ++j) if (j + map[i][0] <= v) dp[j + map[i][0]] = Math.Max(dp[j + map[i][0]], dp[j] + map[i][1]);
        }
        WriteLine(dp.Max());
    }
}