#include <iostream>
#include <vector>
#include <set>
#include <algorithm>
using namespace std;
using ll = long long;
using vll = vector<ll>;
using pll = pair<ll, ll>;
#define sz(x) int(x.size())
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int n, m, o;
cin >> n >> m >> o;
multiset<pll> rooms; //(capacity, upkeep)
for(int i = 1; i <= n; i++)
{
ll c, p;
cin >> c >> p;
rooms.insert({p, c});
}
vector<pll> offers(m); //(capacity requirement = first, gain = second)
for(int j = 0; j < m; j++)
{
cin >> offers[j].second >> offers[j].first;
}
sort(offers.begin(), offers.end(), [] (pll U, pll V)
{
return U.second > V.second;
});
ll res = 0;
vector<ll> options;
for(pll z : offers)
{
// cerr << "offer = " << z.first << ' ' << z.second << '\n';
ll capreq = z.first;
ll gain = z.second;
auto f = rooms.lower_bound({capreq, -1});
if(f == rooms.end()) continue;
if(gain > f->second)
{
options.push_back(gain - f->second);
}
rooms.erase(f);
}
sort(options.begin(), options.end());
for(int i = sz(options)-1; i >= 0 && i >= sz(options)-o; i--)
res += options[i];
cout << res << '\n';
}
