#include<bits/stdc++.h>
#define ll long long
#define f first
#define s second
#define pb push_back
using namespace std;
ll n,m,s,prea[500005],preb[500005],ans,cur,fix[500005],raod,ind;
ll af[500005],bf[500005],pown = 1;
pair<ll,ll>t[5000005],a[400005],b[400005];
void upd(ll x){
if(!x)return;
t[x].f = t[2 * x].f + t[2 * x + 1].f;
t[x].s = t[2 * x].s + t[2 * x + 1].s;
upd(x / 2);
}
void ad(ll x){
ll f = af[x] - bf[x] + 100005;
t[pown + f - 1].f = 1;
t[pown + f - 1].s = af[x] - bf[x];
upd((pown + f - 1) / 2);
}
void rem(ll x){
ll f = af[x] - bf[x] + 100005;
t[pown + f - 1].f = 0;
t[pown + f - 1].s = 0;
upd((pown + f - 1) / 2);
}
void countt(ll x,ll L,ll R){
if(t[x].f <= raod){
raod -= t[x].f;
cur += t[x].s;
return;
}
if(L == R)return;
if(t[2 * x].f >= raod)
countt(2 * x , L , (L + R) / 2);
else {
cur += t[2 * x].s;
raod -= t[2 * x].f;
countt(2 * x + 1 , (L + R) / 2 + 1 , R);
}
}
int main(){
ios::sync_with_stdio(false);
cin >> n >> m >> s;
while(pown <= 1000000)
pown *= 2;
for(int i=1; i<=n; i++){
cin >> a[i].f >> b[i].f;
af[i] = a[i].f;
bf[i] = b[i].f;
a[i].s = b[i].s = i;
}
sort(a + 1 , a + n + 1);
reverse(a + 1 , a + n + 1);
sort(b + 1 , b + n + 1);
reverse(b + 1 , b + n + 1);
for(int i=1; i<=n; i++)
prea[i] = prea[i - 1] + a[i].f;
for(int i=1; i<=n; i++)
preb[i] = preb[i - 1] + b[i].f;
for(int i=1; i<=m; i++)
fix[a[i].s] = 1;
ll saerto = 0 , sumb = 0;
for(int i=1; i<=n; i++){
fix[b[i].s]++;
if(fix[b[i].s] == 2){
saerto++;
if(m + i - saerto > s + m){
saerto--;
fix[b[i].s]--;
break;
}
ad(b[i].s);
}
if(m + i - saerto > s + m){fix[b[i].s]--;break;}
if(m + i - saerto <= s + m)ind = i;
}
for(int i=1; i<=ind; i++)
if(fix[b[i].s] == 1)
sumb += b[i].f;
for(int i=m; i<=n; i++){
if(i > m){
fix[a[i].s]++;
if(fix[a[i].s] == 2){
saerto++;
sumb -= bf[a[i].s];
ad(a[i].s);
}
}
while(i + ind - saerto > s + m){
fix[b[ind].s]--;
if(fix[b[ind].s] == 1){
rem(b[ind].s);
saerto--;
}
else {
sumb -= b[ind].f;
}
ind--;
if(ind < s)break;
}
if(ind < s)break;
raod = i - m;
cur = 0;
countt(1 , 1 , pown);
ans = max(ans , prea[i] + sumb - cur);
}
cout << ans << endl;
return 0;
}
