/* -*- coding: utf-8 -*-
 *
 * 1947.cc:  No.1947 質より種類数 - yukicoder
 */

#include<cstdio>
#include<algorithm>
 
using namespace std;

/* constant */

const int MAX_N = 5000;
const int MAX_V = 5000;

/* typedef */

typedef long long ll;

/* global variables */

int vs[MAX_N], ws[MAX_N];
ll dp[MAX_V + 1];

/* subroutines */

template <typename T>
inline void setmax(T &a, T b) { if (a < b) a = b; }

/* main */

int main() {
  int n, v, c;
  scanf("%d%d%d", &n, &v, &c);
  for (int i = 0; i < n; i++) scanf("%d%d", vs + i, ws + i);

  fill(dp, dp + v + 1, -1);
  dp[0] = 0;

  for (int i = 0; i < n; i++) {
    int w = c + ws[i];
    for (int j = v - vs[i]; j >= 0; j--)
      if (dp[j] >= 0)
	setmax(dp[j + vs[i]], dp[j] + w);
  }

  for (int j = 0; j <= v; j++)
    for (int i = 0; i < n; i++)
      if (j >= vs[i] && dp[j - vs[i]] >= 0)
	setmax(dp[j], dp[j - vs[i]] + ws[i]);

  ll maxd = 0;
  for (int j = 0; j <= v; j++) setmax(maxd, dp[j]);

  printf("%lld\n", maxd);
  return 0;
}