#include <bits/stdc++.h>
#define debug(x) cerr << #x << " " << x << "\n"
#define debugs(x) cerr << #x << " " << x << " "
using namespace std;
typedef long long ll;
typedef pair <ll, ll> pii;
typedef pair <long double, pii> muchie;
const ll NMAX = 300001;
const ll VMAX = 1000001;
const ll INF = (1LL << 60);
const ll MOD = 1000000007;
const ll BLOCK = 447;
const ll nr_of_bits = 21;
pii v[NMAX];
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int n, m, s, i;
cin >> n >> m >> s;
for(i = 1; i <= n; i++){
cin >> v[i].first >> v[i].second;
}
sort(v + 1, v + n + 1);
priority_queue <int> st;
ll sol = 0;
for(i = n; i >= n - m + 1; i--){
sol += v[i].first;
st.push(v[i].second - v[i].first);
}
multiset <pii> bestm, bests;
for(i = n - m; i >= 1; i--){
bestm.insert(v[i]);
bests.insert({v[i].second, v[i].first});
}
for(i = 1; i <= s; i++){
ll sterge = st.top() + (*bestm.rbegin()).first;
ll nou = (*bests.rbegin()).first;
if(sterge > nou){
sol += sterge;
pii x = *bestm.rbegin();
bestm.erase(bestm.find(*bestm.rbegin()));
bests.erase(bests.find({x.second, x.first}));
st.pop();
st.push(x.second - x.first);
}else{
sol += nou;
pii x = *bests.rbegin();
bests.erase(bests.find(*bests.rbegin()));
bestm.erase(bestm.find({x.second, x.first}));
}
}
cout << sol;
return 0;
}
