#include<bits/stdc++.h>
using namespace std;
const int NRIT = 4e5;
const int proba = 1000;
const int NRSHUFFLES = 100;
int n,m,s;
pair<int,pair<int,int>> v[300005];
int unde[300005];
mt19937 rnd(293123);
signed main()
{
ios_base::sync_with_stdio(0);cin.tie(0);
cin>>n>>m>>s;
int a,b;
for(int i=1;i<=n;i++)
{
cin>>a>>b;
v[i] = {a-b,{a,b}};
}
sort(v+1,v+1+n);
long long mxm=0;
for(int pas2=0;pas2<NRSHUFFLES;pas2++)
{
for(int i=1;i<=n;i++)
unde[i]=0;
for(int i=1;i<=s;i++)
unde[i]=2;
for(int i=1;i<=m;i++)
unde[n-i+1]=1;
for(int pas=0;pas<NRIT;pas++)
{
int x = rnd()%n + 1;
int y = rnd()%n + 1;
if(unde[x]==unde[y])
continue;
if(unde[y]==0)
swap(x,y);
if(unde[x]==0)
{
if(unde[y]==1)
{
if(v[x].second.first - v[y].second.first > 0 || rnd()%proba==0)
swap(unde[x],unde[y]);
}
else
{
if(v[x].second.second - v[y].second.second > 0 || rnd()%proba==0)
swap(unde[x],unde[y]);
}
}
else
{
if(unde[x]==2)
swap(x,y);
if(v[x].second.second - v[x].second.first + v[y].second.first - v[y].second.second > 0 || rnd()%proba==0)
{
swap(unde[x],unde[y]);
}
}
}
long long sum=0;
for(int i=1;i<=n;i++)
{
if(unde[i]==1)
sum += v[i].second.first;
else if(unde[i]==2)
sum += v[i].second.second;
}
mxm=max(mxm,sum);
random_shuffle(v+1,v+1+n);
}
cout<<mxm;
return 0;
}
