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