import collections


def read_data():
    N = int(input())
    BCs = []
    for n in range(N):
        b, c = map(int, input().split())
        BCs.append((b, c))
    M = int(input())
    Es = [0] * N
    for m in range(M):
        d, e = map(int, input().split())
        Es[d] += (1 << e)
    return N, BCs, Es


def solve(N, BCs, Es):
    dp = collections.defaultdict(int)
    dp[0] = 0
    for i in range(N):
        b, c = BCs[i]
        mask = Es[i]
        new_dp = collections.defaultdict(int)
        idx = 1 << i
        for key, val in dp.items():
            tour = key & idx
            new_key = key - tour
            new_val = val if tour else (val + c)
            if new_val > new_dp[new_key]: new_dp[new_key] = new_val
            new_key |= mask
            new_val = val + b
            if new_val > new_dp[new_key]: new_dp[new_key] = new_val
        dp = new_dp
    return dp[0]

N, BCs, Es = read_data()
print(solve(N, BCs, Es))