#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;

typedef long long ll;
typedef modint998244353 mint;
const int MOD = 1000000007;
#define all(x) x.begin(), x.end()
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
const int inf = 1 << 30;
const ll INF = 1LL << 60;
const int dx[8] = {1, 0, -1, 0, -1, -1, 1, 1};
const int dy[8] = {0, 1, 0, -1, -1, 1, -1, 1};
template <class T> bool chmax(T& a, const T& b) { if (a < b) { a = b; return 1; } return 0; }
template <class T> bool chmin(T& a, const T& b) { if (b < a) { a = b; return 1; } return 0; }

int main(){
    int n, V, c;
    cin >> n >> V >> c;
    vector<int> v(n), w(n);
    rep(i, n) cin >> v[i] >> w[i];

    vector<vector<ll>> dp(2 * n + 1, vector<ll>(V + 1, 0));
    rep(i, n){
        rep(j, V + 1){
            if(j + v[i] <= V) chmax(dp[i][j + v[i]], dp[i][j] + w[i]);
            chmax(dp[i + 1][j], dp[i][j]);
        }
    }
    rep(i, n){
        rep(j, V + 1){
            if(j + v[i] <= V) chmax(dp[n + i + 1][j + v[i]], dp[n + i][j] + w[i] + c);
            chmax(dp[n + i + 1][j], dp[n + i][j]);
        }
    }

    ll ans = 0;
    rep(i, V + 1) chmax(ans, dp[2 * n][i]);

    cout << ans << endl;

    return 0;
}