import sys
from collections import defaultdict

def main():
    N = int(sys.stdin.readline())
    B = []
    C = []
    for _ in range(N):
        b, c = map(int, sys.stdin.readline().split())
        B.append(b)
        C.append(c)
    M = int(sys.stdin.readline())
    constraints = [[] for _ in range(N)]
    for _ in range(M):
        D, E = map(int, sys.stdin.readline().split())
        constraints[D].append(E)
    
    # Initialize DP: dictionary where key is mask, value is max satisfaction
    dp = {0: 0}
    
    for i in range(N):
        next_dp = defaultdict(int)
        for mask, current_max in dp.items():
            # Option 1: do not include i
            if mask in next_dp:
                if current_max > next_dp[mask]:
                    next_dp[mask] = current_max
            else:
                next_dp[mask] = current_max
            
            # Option 2: include i
            if (mask >> i) & 1:
                # Must take the tour
                new_mask = mask
                for e in constraints[i]:
                    new_mask |= (1 << e)
                new_sat = current_max + B[i]
                if new_mask in next_dp:
                    if new_sat > next_dp[new_mask]:
                        next_dp[new_mask] = new_sat
                else:
                    next_dp[new_mask] = new_sat
            else:
                # Option a: take the tour
                new_mask_a = mask
                for e in constraints[i]:
                    new_mask_a |= (1 << e)
                new_sat_a = current_max + B[i]
                if new_mask_a in next_dp:
                    if new_sat_a > next_dp[new_mask_a]:
                        next_dp[new_mask_a] = new_sat_a
                else:
                    next_dp[new_mask_a] = new_sat_a
                
                # Option b: do not take the tour
                new_mask_b = mask
                new_sat_b = current_max + C[i]
                if new_mask_b in next_dp:
                    if new_sat_b > next_dp[new_mask_b]:
                        next_dp[new_mask_b] = new_sat_b
                else:
                    next_dp[new_mask_b] = new_sat_b
        
        # Update dp to next_dp, keeping only the maximum for each mask
        dp = {}
        for mask in next_dp:
            if mask in dp:
                if next_dp[mask] > dp[mask]:
                    dp[mask] = next_dp[mask]
            else:
                dp[mask] = next_dp[mask]
    
    if dp:
        print(max(dp.values()))
    else:
        print(0)

if __name__ == '__main__':
    main()