#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i,n) for (int i=0;i<(int)(n);i++)

int main(){
  ll n,p,c;
  cin>>n>>p>>c;
  vector<ll> v(n);
  vector<ll> w(n);
  rep(i,n) cin>>v.at(i)>>w.at(i);
  vector<vector<ll>> dp(2*n+1,vector<ll>(p+1,0));
  rep(i,n){
    rep(j,p){
      if(j+v.at(i)<=p) dp.at(i+1).at(j+v.at(i))=max(dp.at(i+1).at(j+v.at(i)),dp.at(i).at(j)+w.at(i)+c);
      dp.at(i+1).at(j+1)=max(dp.at(i+1).at(j+1),dp.at(i).at(j+1));
    }
  }  
  rep(i,n){
    rep(j,p){
      if(j+v.at(i)<=p) {
        dp.at(n+i+1).at(j+v.at(i))=max(dp.at(n+i+1).at(j+v.at(i)),dp.at(n+i).at(j)+w.at(i));
        dp.at(n+i).at(j+v.at(i))=max(dp.at(n+i).at(j+v.at(i)),dp.at(n+i).at(j)+w.at(i));
      }
      dp.at(n+i+1).at(j+1)=max(dp.at(n+i+1).at(j+1),dp.at(n+i).at(j+1));
    }
  }
  /*
  for(auto dd:dp){
    for(auto d:dd) cout<<d<<" ";
    cout<<endl;
  }
  */
  cout<<dp[2*n][p]<<endl;
}