#include<bits/stdc++.h>
#define ios ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0)
#define dec(x, y) fixed << setprecision((y)) << (x)
#define xx first
#define yy second
#define srt(v) sort((v).begin(), (v).end())
#define srtr(v) sort((v).rbegin(), (v).rend())
#define pb push_back
#define popb pop_back
#define sz(a) (int)(a).size()
#define len(a) (int)(a).length()
#define mp make_pair
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
int n, m, s;
pll x[300010];
set<pll> naja, najb, raz;
ll rez;
int main() {
ios;
cin >> n >> m >> s;
for(int i=0; i<n; ++i) {
cin >> x[i].xx >> x[i].yy;
}
sort(x, x+n, greater<pll>());
for(int i=0; i<m; ++i) {
rez+=x[i].xx;
raz.insert({x[i].yy-x[i].xx, (ll)i});
}
for(int i=m; i<n; ++i) {
naja.insert({x[i].xx, (ll)i});
najb.insert({x[i].yy, (ll)i});
}
int br=0;
while(true) {
++br;
if(s==0) break;
pll pr=*prev(najb.end());
pll dr=*prev(raz.end());
pll tr=*prev(naja.end());
if(pr.xx>dr.xx+tr.xx && pr.xx>0LL) {
rez+=pr.xx;
--s;
najb.erase(prev(najb.end()));
auto it=naja.find({x[pr.yy].xx, pr.yy});
if(it!=naja.end()) naja.erase(it);
}
else if(dr.xx+tr.xx>0LL) {
rez+=dr.xx+tr.xx;
--s;
raz.erase(prev(raz.end()));
naja.erase(prev(naja.end()));
raz.insert({x[tr.yy].yy-x[tr.yy].xx, tr.yy});
}
else break;
//if(br>=1000000) {cout << 1; break;}
}
cout << rez;
return 0;
}
