#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pll = pair<ll, ll>;
#define drep(i, cc, n) for (ll i = (cc); i <= (n); ++i)
#define rep(i, n) drep(i, 0, n - 1)
#define all(a) (a).begin(), (a).end()
#define pb push_back
#define fi first
#define se second

const ll MOD = 1000000007;
const ll MOD2 = 998244353;
const ll INF = 1LL << 60;
const ll MAX_N = 5000;
const ll MAX_V = 5000;

ll dp[MAX_N+1][MAX_V+1][2];

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

    vector<ll> v(N), w(N);
    rep(i, N) cin >> v[i] >> w[i];

    memset(dp, -1, sizeof(dp));
    dp[0][0][0] = 0;
    dp[0][0][1] = 0;
    for(ll i=1; i<=N; i++){
        for(ll j=0; j<=V; j++){
            dp[i][j][0] = max(dp[i-1][j][0], dp[i-1][j][1]);
            if(0 <= j-v[i-1]){
                if(dp[i][j-v[i-1]][0] != -1){
                    dp[i][j][0] = max(dp[i][j][0], dp[i][j-v[i-1]][0]+w[i-1]);
                }

                if(dp[i][j-v[i-1]][1] != -1){
                    dp[i][j][0] = max(dp[i][j][0], dp[i][j-v[i-1]][1]+w[i-1]);
                }

                if(dp[i-1][j-v[i-1]][0] != -1){
                    dp[i][j][1] = max(dp[i][j][1], dp[i-1][j-v[i-1]][0]+C+w[i-1]);
                }

                if(dp[i-1][j-v[i-1]][1] != -1){
                    dp[i][j][1] = max(dp[i][j][1], dp[i-1][j-v[i-1]][1]+C+w[i-1]);
                }
            }
        }
    }

    ll ans = -INF;
    for(ll i=1; i<=N; i++) for(ll j=0; j<=V; j++) ans = max(ans, max(dp[i][j][0], dp[i][j][1]));
    cout << ans << endl;
}