#include <cassert>
#include <cmath>
#include <algorithm>
#include <iostream>
#include <iomanip>
#include <climits>
#include <map>
#include <queue>
#include <set>
#include <cstring>
#include <vector>

using namespace std;
typedef long long ll;

int main() {
  ll N, V, C;
  cin >> N >> V >> C;

  ll VS[N];
  ll WS[N];

  for (int i = 0; i < N; ++i) {
    cin >> VS[i] >> WS[i];
  }

  ll dp[V + 1];
  memset(dp, -1, sizeof(dp));
  dp[0] = 0;

  for (int i = 0; i < N; ++i) {
    for (int v = V - VS[i]; v >= 0; --v) {
      if (dp[v] < 0) continue;

      ll nv = v + VS[i];
      ll nw = dp[v] + WS[i] + C;
      dp[nv] = max(dp[nv], nw);
    }
  }

  for (int i = 0; i < N; ++i) {
    for (int v = 0; v <= V - VS[i]; ++v) {
      if (dp[v] < 0) continue;

      ll nv = v + VS[i];
      ll nw = dp[v] + WS[i];
      dp[nv] = max(dp[nv], nw);
    }
  }

  ll ans = 0;

  for (int v = 0; v <= V; ++v) {
    if (dp[v] < 0) continue;

    ans = max(ans, dp[v]);
  }

  cout << ans << endl;

  return 0;
}