#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <limits.h>
#include <stack>
#include <queue>
#include <map>
#include <set>
#include <algorithm>
#include <string>
#include <functional>
#include <vector>
#include <numeric>
#include <deque>
#include <bitset>
#include <iostream>
using namespace std;
typedef long long lint;
typedef long double llf;
typedef pair<int, int> pi;
int n, m, s;
pi a[300005];
multiset<pi> lev1, lev2;
int main(){
cin >> n >> m >> s;
for(int i=0; i<n; i++){
scanf("%d %d",&a[i].first, &a[i].second);
}
sort(a, a+n);
reverse(a, a+n);
lint ret = 0, tret = 0;
for(int i=0; i<m; i++){
ret += a[i].first;
lev2.insert(pi(a[i].first, a[i].second));
}
for(int i=m; i<n; i++){
lev1.insert(pi(a[i].first, a[i].second));
}
tret = ret;
for(int i=0; i<s; i++){
int prof1 = -1e9, prof2 = -1e9, prof3 = -1e9;
pi pp1, pp2, pp3;
for(auto &i : lev1){
if(prof1 < i.second){
prof1 = i.second;
pp1 = i;
}
if(prof2 < i.first){
prof2 = i.first;
pp2 = i;
}
}
for(auto &i : lev2){
if(prof3 < i.second - i.first){
prof3 = i.second - i.first;
pp3 = i;
}
}
if(prof1 > prof2 + prof3){
ret += prof1;
lev1.erase(pp1);
}
else{
ret += prof2 + prof3;
lev2.erase(pp3);
lev2.insert(pp2);
lev1.erase(pp2);
}
tret = max(tret, ret);
// case 1. get s from empty set
// case 2. get s from nonempty + get m from empty
// case 3.
}
cout<< tret;
}
