#include <bits/stdc++.h>
#define fi first
#define se second
#define mp make_pair
#define lo long long
#define inf 1000000000
#define md 1000000007
#define pb push_back
#define li 300005
#define ii pair< pair<lo int,lo int> ,lo int>
using namespace std;
lo int n,m,s,x[li],y[li],vis[li],cev,mx;
ii p[li],z[li];
bool cmp(ii a,ii b){
if(y[a.se]>y[b.se]) return true;
return false;
}
//~ bool cmp2(ii a,ii b){
//~ if(a.fi.se-a.fi.fi>b.fi.se-b.fi.fi) return true;
//~ if(a.fi.se>=b.fi.se) return true;
//~ if(a.fi.se<b.fi.se) return false;
//~ return false;
//}
int main(){
scanf("%lld %lld %lld",&n,&m,&s);
for(int i=1;i<=n;i++){
scanf("%lld %lld",&x[i],&y[i]);
p[i]=mp(mp(x[i]-y[i],x[i]),i);
z[i]=mp(mp(x[i]-y[i],x[i]),i);
}
sort(z+1,z+n+1,greater<ii>());
//~ for(int i=1;i<=n;i++){
//~ printf("%lld %lld\n",z[i].fi.se,z[i].se);
//~ }
//~ return 0;
for(int i=1;i<=m;i++){
//printf("%lld %lld\n",z[i].fi.fi,z[i].fi.se);
cev+=z[i].fi.se;
vis[z[i].se]=1;
}
sort(z+1,z+n+1,cmp);
int cnt=0;
for(int i=1;i<=n;i++){
//printf("%d %d %d\n",z[i].fi.fi,z[i].fi.se,z[i].se);
if(cnt==s) break;
if(vis[z[i].se]==1) continue;
cnt++;
cev+=y[z[i].se];
}
mx=cev;
//memset(vis,0,sizeof(vis));
//cev=0;
//~ sort(z+1,z+n+1,cmp);
//~ for(int i=1;i<=s;i++){
//~ cev+=z[i].fi.se;
//~ vis[z[i].se]=1;
//~ }
//~ //sort(z+1,z+n+1,cmp);
//~ cnt=0;
//~ for(int i=1;i<=n;i++){
//~ //printf("%d %d %d\n",z[i].fi.fi,z[i].fi.se,z[i].se);
//~ if(cnt==m) break;
//~ if(vis[z[i].se]==1) continue;
//~ cnt++;
//~ cev+=z[i].fi.fi;
//~ }
//~ mx=max(mx,cev);
printf("%lld\n",mx);
return 0;
}
