#include <bits/stdc++.h>
#define int long long
using namespace std;
struct area{
int a, b;
};
int32_t main(){
int N, M, S;
cin >> N >> M >> S;
vector<area> A;
for(int i = 0; i < N; i++){
int a, b; cin >> a >> b;
A.push_back({a, b});
}
sort(A.begin(), A.end(), [](area x, area y){
return x.a > y.a;
});
int ans = 0;
for(int i = 0; i < M; i++){
ans += A[i].a;
}
priority_queue<pair<int, int>> pq, pqe, pq1, pq1e, pq2, pq2e;
for(int i = M; i < N; i++){
pq.push({A[i].a, i});
}
for(int i = 0; i < M; i++){
pq1.push({A[i].b - A[i].a, i});
}
for(int i = M; i < N; i++){
pq2.push({A[i].b, i});
}
for(int i = 0; i < S; i++){
while(pq.size() && pqe.size() && pq.top() == pqe.top()) pq.pop(), pqe.pop();
while(pq1.size() && pq1e.size() && pq1.top() == pq1e.top()) pq1.pop(), pq1e.pop();
while(pq2.size() && pq2e.size() && pq2.top() == pq2e.top()) pq2.pop(), pq2e.pop();
if(pq1.top().first + pq.top().first > pq2.top().first){
ans += pq1.top().first + pq.top().first; pq1.pop(); int added = pq.top().second; pq.pop(); pq2e.push({A[added].b, added}); pq1.push({A[added].b - A[added].a, added});
}else{
ans += pq2.top().first; int added = pq.top().second; pqe.push({A[added].a, added}); pq2.pop();
}
}
cout << ans << endl;
}
