#include<bits/stdc++.h>
using namespace std;
const int NRIT = 3e7;
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);
for(int i=1;i<=s;i++)
{
unde[i]=2;
}
for(int i=1;i<=m;i++)
{
unde[i]=1;
}
for(int pas=0;pas<NRIT;pas++)
{
int x = rnd()%n;
int y = rnd()%n;
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)
swap(unde[x],unde[y]);
}
else
{
if(v[x].second.second - v[y].second.second > 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)
{
swap(unde[x],unde[y]);
}
}
}
long long sum=0;
for(int i=0;i<n;i++)
{
if(unde[i]==1)
sum += v[i].second.first;
else if(unde[i]==2)
sum += v[i].second.second;
}
cout<<sum;
return 0;
}
