import sys
input = sys.stdin.readline

from collections import Counter

N=int(input())

M=[list(map(int,input().split())) for i in range(N)]

k=int(input())

E=[0]*N

for i in range(k):
    d,e=map(int,input().split())
    E[d]^=(1<<e)

DP=Counter()
DP[0]=0

for i in range(N):
    a,b=M[i]
    NDP=Counter()

    for c in DP:
        now=DP[c]

        if c & (1<<i) != 0:
            toc=c^(1<<i)
            
            # tourに行く

            NDP[toc|E[i]]=max(NDP[toc|E[i]],now+a)

            # 国へ行かない

            NDP[toc]=max(NDP[toc],now)

        else:
            # tourに行く

            NDP[c|E[i]]=max(NDP[c|E[i]],now+a)

            # 国へ行く

            NDP[c]=max(NDP[c],now+b)

    DP=NDP

    #print(DP)


print(max(DP.values()))