//outsider
#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());
multiset<ll>q;
multiset <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>fat,sad;
fat=*os1.rbegin();
sad=*os2.rbegin();
ll f1=-*q.begin();
if(f1+fat.x>sad.x)
{
ans+=f1+fat.x;
q.erase(q.begin());
ll p=fat.y-fat.x;
q.insert(-p);
os1.erase(os1.find(fat));
os2.erase(os2.find({fat.y, fat.x}));
}
else{
ans +=sad.x;
os2.erase(os2.find(sad));
os1.erase(os1.find({sad.y, sad.x}));
}
}
cout<< ans;
return 0;
}
