#include<iostream>
#include<string>
#include<cstdio>
#include<vector>
#include<cmath>
#include<algorithm>
#include<functional>
#include<iomanip>
#include<queue>
#include<ciso646>
#include<random>
#include<map>
#include<set>
#include<bitset>
#include<stack>
#include<unordered_map>
#include<utility>
#include<cassert>
#include<complex>
#include<numeric>
using namespace std;

//#define int long long
typedef long long ll;

typedef unsigned long long ul;
typedef unsigned int ui;
const ll mod = 1000000007;
const ll INF = mod * mod;
typedef pair<int, int>P;
#define stop char nyaa;cin>>nyaa;
#define rep(i,n) for(int i=0;i<n;i++)
#define per(i,n) for(int i=n-1;i>=0;i--)
#define Rep(i,sta,n) for(int i=sta;i<n;i++)
#define rep1(i,n) for(int i=1;i<=n;i++)
#define per1(i,n) for(int i=n;i>=1;i--)
#define Rep1(i,sta,n) for(int i=sta;i<=n;i++)
#define all(v) (v).begin(),(v).end()
typedef pair<ll, ll> LP;
typedef long double ld;
typedef pair<ld, ld> LDP;
const ld eps = 1e-12;
const ld pi = acos(-1.0);

ll mod_pow(ll a, ll n, ll m = mod) {
	ll res = 1;
	while (n) {
		if (n & 1)res = res * a%m;
		a = a * a%m; n >>= 1;
	}
	return res;
}

struct modint {
	ll n;
	modint() :n(0) { ; }
	modint(ll m) :n(m) {
		if (n >= mod)n %= mod;
		else if (n < 0)n = (n%mod + mod) % mod;
	}
	operator int() { return n; }
};
bool operator==(modint a, modint b) { return a.n == b.n; }
modint operator+=(modint &a, modint b) { a.n += b.n; if (a.n >= mod)a.n -= mod; return a; }
modint operator-=(modint &a, modint b) { a.n -= b.n; if (a.n < 0)a.n += mod; return a; }
modint operator*=(modint &a, modint b) { a.n = ((ll)a.n*b.n) % mod; return a; }
modint operator+(modint a, modint b) { return a += b; }
modint operator-(modint a, modint b) { return a -= b; }
modint operator*(modint a, modint b) { return a *= b; }
modint operator^(modint a, int n) {
	if (n == 0)return modint(1);
	modint res = (a*a) ^ (n / 2);
	if (n % 2)res = res * a;
	return res;
}

ll inv(ll a, ll p) {
	return (a == 1 ? 1 : (1 - p * inv(p%a, a)) / a + p);
}
modint operator/(modint a, modint b) { return a * modint(inv(b, mod)); }
const int max_n = 2000010;
modint fact[max_n], factinv[max_n];
void init_f() {
	fact[0] = modint(1);
	for (int i = 0; i < max_n - 1; i++) {
		fact[i + 1] = fact[i] * modint(i + 1);
	}
	factinv[max_n - 1] = modint(1) / fact[max_n - 1];
	for (int i = max_n - 2; i >= 0; i--) {
		factinv[i] = factinv[i + 1] * modint(i + 1);
	}
}
modint comb(int a, int b) {
	if (a < 0 || b < 0 || a < b)return 0;
	return fact[a] * factinv[b] * factinv[a - b];
}

int dx[4] = { 0,1,0,-1 };
int dy[4] = { 1,0,-1,0 };

bool exi[40][40];
void solve() {
	int n; cin >> n;
	vector<int> b(n), c(n);
	rep(i, n)cin >> b[i] >> c[i];
	rep(i, n)exi[i][i] = true;
	int m; cin >> m;
	rep(i, m) {
		int a, b; cin >> a >> b; exi[a][b] = true;
	}
	int d1 = n/2;
	int d2 = n - d1;
	vector<int> memo(1 << d2);
	vector<int> ban(d2);
	rep(i, d2) {
		rep(j, d2) {
			if (exi[j+d1][i+d1])ban[i] |= (1 << j);
		}
	}
	rep(i, (1 << d2)) {
		int bs = 0;
		rep(j, d2)if (i&(1 << j)) {
			bs |= ban[j];
		}
		int sum = 0;
		rep(j, d2) {
			if (i&(1 << j)) {
				sum += c[j + d1];
			}
			else if (bs&(1 << j)) {
				//
			}
			else {
				sum += b[j + d1];
			}
		}
		memo[i] = sum;
	}
	rep(i, 1 << d2) {
		rep(j, d2)if ((i&(1 << j))==0) {
			int ni = i ^ (1 << j);
			memo[ni] = max(memo[ni], memo[i]);
		}
	}
	vector<int> selfs(d1), tos(d1);
	rep(i, d1) {
		rep(j, d1)if (exi[i][j])selfs[i] ^= (1 << j);
		rep(j, d2)if (exi[i][j + d1])tos[i] ^= (1 << j);
	}
	int ans = 0;
	rep(i, (1 << d1)) {
		int s = 0;
		int t = 0;
		rep(j, d1) {
			if (i&(1 << j)) {
				s |= selfs[j];
				t |= tos[j];
			}
		}
		int sum = 0;
		rep(j, d1) {
			if (i&(1 << j)) {
				sum += b[j];
			}
			else if (s&(1 << j)) {
				//
			}
			else {
				sum += c[j];
			}
		}
		//cout << i << " " << t << "\n";
		sum += memo[(1<<d2)-1-t];
		ans = max(ans, sum);
	}
	cout << ans << "\n";
}


signed main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	//cout << fixed << setprecision(7);
	init_f();
	//init();
	//experi();
	//int t; cin >> t; rep(i, t)solve();
	solve();
	stop
		return 0;
}