#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
typedef int64_t lint;
#define rep(i, n) for(int i=0; i<n; i++)
#define repx(i, l, n) for(int i=l; i<n; i++)
#define all(v) v.begin(), v.end()
#define show(x) cout << #x << ": " << x << endl;
#define list(x) cout << #x << ": " << x << "  ";
#define pb push_back
using vi = vector<lint>;
using vvi = vector<vector<lint>>;
template<class T> inline void vin(vector<T>& v) { rep(i, v.size()) cin >> v.at(i); }
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
template<class T> inline void drop(T x) { cout << x << endl; exit(0); }
template<class T> void vout(vector<T> v) { rep(i, v.size()) { cout << v.at(i) << ' '; } cout << endl; }
constexpr lint LINF = LLONG_MAX/2;
using pint = pair<double, lint>;
using vp = vector<pint>;

int main() {
	lint N, V, C;
	cin >> N >> V >> C;
	vi v(N), w(N);

	lint a=0, b=0, c=0, x, y, z;
	rep(i, N) cin >> v[i] >> w[i];
	vi dp(V+1);
	rep(i, N) {
		for (int j = V; j >= 0; j--) {
			if (j+v[i] < V) chmax(dp[j+v[i]], dp[j]+w[i]+C);
		}
	}
	vp p(N);
	rep(i, N) {
		p[i] = {w[i]/v[i], i};
	}
	sort(all(p), greater());
	rep(i, N) {
		z = p[i].second;
		for (int j = V; j >= 0; j--) {
			if (j+v[z] < V) {
				x = (V-j)/v[z];
				chmax(dp[j+v[z]*x], dp[j]+w[z]*x);
			}
		}
	}
	rep(i, V+1) chmax(a, dp[i]);
	std::cout << a << '\n';
}