#include <algorithm>
#include <iostream>
#include <cstdio>
#include <map>
#include <numeric>
#include <cmath>
#include <set>
#include <sstream>
#include <string>
#include <vector>
#include <queue>
#include <stack>
#include <complex>
#include <string.h>
#include <unordered_set>
#include <unordered_map>
#include <bitset>
#include <iomanip>
#include <sys/time.h>
#include <random>
using namespace std;

#define endl '\n'
#define ALL(v) (v).begin(), (v).end()
#define RALL(v) (v).rbegin(), (v).rend()
#define UNIQ(v) (v).erase(unique((v).begin(), (v).end()), (v).end())

typedef long long ll;
typedef long double ld;
typedef pair<int, ll> P;
typedef complex<double> comp;
typedef vector< vector<ld> > matrix;
struct pairhash {
public:
    template<typename T, typename U>
    size_t operator()(const pair<T, U> &x) const {
	size_t seed = hash<T>()(x.first);
	return hash<U>()(x.second) + 0x9e3779b9 + (seed<<6) + (seed>>2);
    }
};
const int inf = 1e9 + 9;
const ll mod = 1e9 + 7;
const double eps = 1e-8;
const double pi = acos(-1);

int n;
int b[50], c[50];
int m;
int d[50*50], e[50*50];

vector<int> g[50];
bool used[50];

unordered_map<P, int, pairhash> memo;
int dp(int k, ll s) {
    if (k >= n) return 0;
    P p = make_pair(k, s);
    if (memo.count(p) == 0) {
        int res;
        ll t = s&(~(1LL<<k));
        for (int i = 0; i < g[k].size(); i++) t |= (1LL<<g[k][i]);
        res = dp(k+1, s&(~(1LL<<k))) + ((s>>k)&1?0:c[k]);
        res = max(res, dp(k+1, t) + b[k]);
        memo[p] = res;
    }
    return memo[p];
}

int solve() {
    for (int i = 0; i < m; i++) g[d[i]].push_back(e[i]);
    return dp(0, 0);
}

void input() {
    cin >> n;
    for (int i = 0; i < n; i++) cin >> b[i] >> c[i];
    cin >> m;
    for (int i = 0; i < m; i++) cin >> d[i] >> e[i];
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout << fixed << setprecision(15);

    input();
    cout << solve() << endl;
}