#include<bits/stdc++.h>

using namespace std;

using ll = long long;
using ld = long double;

#define rep(i, a, b) for(ll i = (ll)a; i < (ll)b; i++)
#define irep(i, v) for(auto i = (v).begin(); i != (v).end(); i++)
#define ALL(v) (v).begin(), (v).end()
#define SZ(v) (ll)(v).size()

const ll INF = 3e18;
const ld EPS = 1e-10;
const ll MOD = 1e9 + 7;
const ld PI = M_PI;

int main(){
  cin.tie(0);
  ios::sync_with_stdio(false);
  srand((unsigned)time(NULL));
  cout << fixed << setprecision(20);

  ll n, vmax, c;
  cin >> n >> vmax >> c;
  vector<ll> v(2 * n), w(2 * n);
  rep(i, 0, n){
    cin >> v[2 * i + 1] >> w[2 * i + 1];
    v[2 * i] = v[2 * i + 1];
    w[2 * i] = w[2 * i + 1] + c;
  }

  vector<vector<ll>> dp(2 * n + 1, vector<ll>(vmax + 1, 0));

  rep(i, 0, 2 * n){
    rep(j, 1, vmax + 1){
      if(i % 2 == 1){
        if(j - v[i] >= 0) dp[i + 1][j] = max({dp[i][j], dp[i + 1][j - v[i]] + w[i], dp[i + 1][j - 1]});
        else dp[i + 1][j] = max(dp[i][j], dp[i + 1][j - 1]);
      }
      else{
        if(j - v[i] >= 0) dp[i + 1][j] = max({dp[i][j], dp[i][j - v[i]] + w[i], dp[i + 1][j - 1]});
        else dp[i + 1][j] = max(dp[i + 1][j], dp[i][j]);
      }
    }
  }

  cout << *max_element(ALL(dp[2 * n])) << endl;

  return 0;
}