#include <bits/stdc++.h>
#define ll long long
#define x first
#define y second
using namespace std;
int main() {
ll n,l,r;
ll ans=0;
vector<pair<ll,ll> >a;
cin>>n>>l>>r;
a.resize(n+1);
for(ll i=1;i<=n;i++)
cin>>a[i].x>>a[i].y;
sort(a.begin()+1,a.end());
reverse(a.begin()+1,a.end());
set<ll>q;
set <pair<ll,ll> > os1,os2;
for(ll i=1;i<=l;i++)
{
ans+=a[i].x;
q.insert(-a[i].y+a[i].x);
}
for(ll i=l+1;i<=n;i++)
{
os1.insert(a[i]);
os2.insert({a[i].y,a[i].x});
}
for (ll i=r;i>0;i--){
pair<ll,ll>ft,sd;
ft=*os1.rbegin();
sd=*os2.rbegin();
ll f1=-*q.begin();
if(f1+ft.x>sd.x)
{
ans+=ft.x+sd.x;
q.erase(q.begin());
os1.erase(os1.find(ft));
os2.erase(os2.find({ft.x, ft.y}));
q.insert(ft.y-ft.x);
}
else{
ans +=sd.x;
os2.erase(os2.find(sd));
os1.erase(os1.find({sd.y, sd.x}));
}
}
cout<< ans;
return 0;
}
