#include <bits/stdc++.h>
#define ff first
#define ss second
using namespace std;
const int maxn = 3e5+10;
typedef pair<int, int> pii;
typedef long long ll;
pii num[maxn];
bool comp(pii a, pii b){return a.first > b.first;}
int main(void)
{
ios::sync_with_stdio(false); cin.tie();
int n, m, s;
cin >> n >> m >> s;
for (int i = 1; i <= n; i++)
cin >> num[i].first >> num[i].second;
sort(num+1, num+n+1, comp);
multiset< pair<int, pii>, greater< pair<int, pii > > > choose; // a was chosen
multiset< pii, greater<pii> > free_a, free_b; // pairs unchosen, ordered by a, then b
ll ans = 0LL;
for (int i = 1; i <= m; i++)
{
ans += num[i].first;
choose.insert({num[i].second-num[i].first, {num[i].first, num[i].second}});
}
for (int i = m+1; i <= n; i++)
{
free_a.insert({num[i].first, num[i].second});
free_b.insert({num[i].second, num[i].first});
}
// pretty confusing
for (int i = 1; i <= s; i++)
{
int x = (*choose.begin()).ff+(*free_a.begin()).ff;
int y = (*free_b.begin()).ff;
if (x > y)
{
ans += x, choose.erase(choose.begin());
int a = (*free_a.begin()).ff;
int b = (*free_a.begin()).ss;
choose.insert({b-a, {a, b}});
free_a.erase(free_a.begin());
free_b.erase(free_b.find({b, a}));
}
else
{
ans += y;
int a = (*free_b.begin()).ss;
int b = (*free_b.begin()).ff;
free_a.erase(free_a.find({a, b}));
free_b.erase(free_b.begin());
}
}
cout << ans << "\n";
}
