#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define vl vector<ll>
#define ff(aa, bb, cc) for(ll aa = bb; aa < cc; aa++)
#define pb push_back
#define all(aaa) aaa.begin(), aaa.end()
#define rall(aaa) aaa.rbegin(), aaa.rend()
#define pll pair<ll, ll>
#define fi first
#define se second
#define vb vector<bool>
#define ed "\n"
#define vs vector<string>
int main(){
ll n, m, o;
cin >> n >> m >> o;
vector<pll> rooms(n), offers(m);
ff(i, 0, n){
ll a, b;
cin >> a >> b;
rooms[i] = {b, a};
}
ff(i, 0, m){
ll a, b;
cin >> a >> b;
offers[i] = {b, a};
}
sort(all(rooms));
sort(all(offers));
priority_queue<ll> pq;
ll id = 0;
vl lis;
for(auto &[p, c] : rooms){ //people cost
while(id < m && offers[id].fi <= p){
pq.push(offers[id].se);
id++;
}
if(!pq.empty()){
ll cur = pq.top();
pq.pop();
ll prof = cur-c;
if(prof > 0) lis.pb(prof);
}
}
sort(rall(lis));
ll sz = lis.size();
ll s = 0;
ff(i, 0, min(sz, o)){
s += lis[i];
}
cout << s;
}
//this problem is absolute cinema
