#include <bits/stdc++.h>
using namespace std;
int main() {
  int N, V, C;
  cin >> N >> V >> C;
  vector<int> v(N), w(N);
  for (int i = 0; i < N; i++) {
    cin >> v[i] >> w[i];
  }
  vector<int> dp(V + 1, 0);
  for (int i = 0; i < N; i++) {
    for (int j = V - v[i]; j >= 0; j--) {
      dp[j + v[i]] = max(dp[j] + C + w[i], dp[j + v[i]]);
    }
    for (int j = 0; j <= V - v[i]; j++) {
      dp[j + v[i]] = max(dp[j] + w[i], dp[j + v[i]]);
    }
  }
  cout << dp[V] << endl;
}