#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];
struct node{
int x, y, i;
};
auto func1 = [](const node &a, const node &b){
if(a.x != b.x) return a.x < b.x;
return a.y > b.y;
};
auto func2 = [](const node &a, const node &b){
if(a.y != b.y) return a.y < b.y;
return a.x > b.x;
};
priority_queue<node, vector<node>, decltype(func1) > pq1 (func1);
priority_queue<node, vector<node>, decltype(func2) > pq2 (func2);
priority_queue<int> lev2;
bool inque[300005];
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;
for(int i=0; i<m; i++){
ret += a[i].first;
lev2.push(a[i].second - a[i].first);
}
for(int i=m; i<n; i++){
inque[i] = 1;
pq1.push({a[i].first, a[i].second, i});
pq2.push({a[i].first, a[i].second, i});
}
for(int i=0; i<s; i++){
while(!inque[pq1.top().i]) pq1.pop();
while(!inque[pq2.top().i]) pq2.pop();
node p1 = pq1.top(), p2 = pq2.top();
if(p2.y >= p1.x + lev2.top()){
ret += p2.y;
inque[p2.i] = 0;
}
else{
ret += p1.x + lev2.top();
inque[p1.i] = 0;
lev2.pop();
lev2.push(p1.y - p1.x);
}
// case 1. get s from empty set
// case 2. get s from nonempty + get m from empty
}
cout<< ret;
}
