#include<bits/stdc++.h>
using namespace std;
using ll=long long;
ll INF=1000000000000000000;
int main(){
  ll n,p,k,t,b,x;cin>>n>>p>>k;vector A(n+1,vector<ll>(k+1,-1));A[0][0]=p;
  for(int i=1;i<=n;i++){
    cin>>t>>b;
    for(int j=k-1;j>=0;j--){
      if(A[i-1][j]>=0){
        A[i][j]=max(A[i][j],A[i-1][j]);
        x=A[i-1][j];
        if(t==1){
          if(INF-x>=b)A[i][j+1]=max(x+b,A[i][j+1]);
        }else if(t==2){
          if(INF/2>=x)A[i][j+1]=max(x*2,A[i][j+1]);
        }
      }
    }
  }
  cout<<A[n][k];
}