/* -*- 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], vws[MAX_V + 1];
ll dp[2][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);

  for (int i = 0; i < n; i++)
    if (vws[vs[i]] < ws[i])
      for (int j = vs[i], w = ws[i]; j <= v; j += vs[i], w += ws[i])
	setmax(vws[j], w);
      
  fill(dp[0], dp[0] + v + 1, -1);
  dp[0][0] = 0;
  int cur = 0, nxt = 1;

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

  copy(dp[cur], dp[cur] + v + 1, dp[nxt]);

  for (int j = 0; j < v; j++)
    if (dp[cur][j] > 0)
      for (int k = 1; j + k <= v; k++)
	setmax(dp[nxt][j + k], dp[cur][j] + vws[k]);
  swap(cur, nxt);

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

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