#include <bits/stdc++.h>
#define int long long
using namespace std;
struct yes
{
int p, v;
};
yes v1[300005];
yes v2[300005];
bool vis1[300005];
bool vis2[300005];
bool luat[300005];
bool cmp(yes a, yes b)
{
return a.v > b.v;
}
bool cmp2(int a, int b)
{
int dif1 = (v1[a].v - v2[a].v), dif2 = (v1[b].v - v2[b].v);
if(dif1 == dif2)
return v1[a].v > v2[a].v;
return dif1 < dif2;
}
bool cmp3(yes a, yes b)
{
return a.v < b.v;
}
signed main()
{
int n, m, s;
cin>>n>>m>>s;
vector<int> p;
int rez = 0;
for(int i = 1; i <= n; i++)
{
cin>>v1[i].v>>v2[i].v;
v1[i].p = v2[i].p = i;
p.push_back(i);
vis1[i] = true;
rez += v1[i].v;
}
sort(p.begin(), p.end(), cmp2);
int cm = n, cs = 0, poz = -1;
while(cm > m && cs < s)
{
poz++;
cm--, cs++;
vis1[p[poz]] = false;
vis2[p[poz]] = true;
rez -= v1[p[poz]].v;
rez += v2[p[poz]].v;
}
if(cm > m)
{
sort(v1 + 1, v1 + n + 1, cmp3);
poz = 0;
while(cm > m)
{
poz++;
if(!vis2[v1[poz].p])
cm--, rez -= v1[poz].v;
}
}
if(cs < s)
{
while(1);
}
cout<<rez;
return 0;
}
