#include<iostream>
#include<bits/stdc++.h>
#define MAXN 300010
using namespace std;
long long dp[MAXN][3];//long long
pair<int,int> state[MAXN][3];
pair<int,int> city[MAXN];
//vector<pair<pair<int,int>,int>> order;
int main()
{
int n,m,s;
ios_base::sync_with_stdio(false);
cin.tie(0);
cin>>n>>m>>s;
state[0][0]={m,s};
state[0][1]={m,s};
state[0][2]={m,s};
for(int i=1;i<=n;i++)
{
cin>>city[i].first>>city[i].second;
state[i][0]={m,s};
state[i][1]={m,s};
state[i][2]={m,s};
//order.push_back({city[i],i});
}
//sort(order.begin(),order.end(),greater<pair<pair<int,int>,int>>());
for(int i=1;i<=n;i++)
{
int mus=city[i].first;
int sp=city[i].second;
for(int j=0;j<3;j++)
{
if(dp[i-1][j]>dp[i][0])
{
dp[i][0]=dp[i-1][j];
state[i][0]=state[i-1][j];
}
if(dp[i-1][j]+mus>dp[i][1] && state[i-1][j].first>0)
{
dp[i][1]=dp[i-1][j]+mus;
state[i][1]=state[i-1][j];
state[i][1].first--;
}
if(dp[i-1][j]+sp>dp[i][2] && state[i-1][j].second>0)
{
dp[i][2]=dp[i-1][j]+sp;
state[i][2]=state[i-1][j];
state[i][2].second--;
}
}
}
long long ans=0;
for(int i=0;i<3;i++)
{
if(dp[n][i]>ans)ans=dp[n][i];
}
cout<<ans<<"\n";
}
