#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define ar array
#define fr first
#define sc second
#define vec vector
#define ret return
#define ins insert
#define mk make_pair
#define pb push_back
#define pf push_front
#define pob pop_back
#define pof pop_front
#define int long long
#define pii pair<int,int>
#define all(s) s.begin(), s.end()
#define allr(s) s.rbegin(), s.rend()
#define NeedForSpeed ios::sync_with_stdio(0),cin.tie(0);
#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>
const int N=1e6+12,INF=1e9,mod = 1e9+7;
bool iswowel(char n){ n = toupper(n); if(n == 'A' || n == 'O' || n == 'U' || n == 'E' || n == 'I') return true; else return false;}
int n,m,k,x,y,l,r,o,ans,res,ok,mx,mn = INF;
int a,b,c,pr[N], suff[N];
vec<pii>v;
bool comp(pii a, pii b){
ret (a.fr - a.sc) > (b.fr - b.sc);
}
main(){
NeedForSpeed
cin>>n>>a>>b;
for(int i=1; i<=n; i++){
cin>>x>>y;
v.pb(mk(x, y));
}
sort(all(v), comp);
priority_queue<int, vec<int>, greater<int> >q;
for(int i=0; i<n; i++){
q.push(v[i].fr);
l += v[i].fr;
if(q.size() > a){
l -= q.top();
q.pop();
}
pr[i] = l;
}
while(!q.empty())q.pop();
for(int i=n-1; i>=0; i--){
q.push(v[i].sc);
r += v[i].sc;
if(q.size() > b){
r -= q.top();
q.pop();
}
suff[i] = r;
}
for(int i=0; i<n; i++){
res = max(res, pr[i] + suff[i+1]);
}
cout<<res<<endl;
return 0;
}
