from collections import deque
d=deque()
n=int(input())
m=10**3+1
maze=[[] for _ in range(m)]
nlst=[list(map(int,input().split())) for _ in range(n)]
q=int(input())
qlst=[list(map(int,input().split())) for _ in range(q)]
INF=float("INF")
dist=[[INF]*m for _ in range(m)]
for i,j in nlst:
	dist[i][j]=0
	d.append((i,j))
# print("A",d)
dy,dx=[0,1,0,-1],[1,0,-1,0]
while d:
	y,x=d.popleft()
	for i in range(4):
		ny,nx=y+dy[i],x+dx[i]
		if not(0<=ny<m and 0<=nx<m):continue
		if dist[ny][nx]!=INF:continue
		dist[ny][nx]=dist[y][x]+1
		d.append((ny,nx))


ans=INF
for i,j in qlst:
	# print("A",i,j,dist[i][j])
	ans=min(dist[i][j],ans)
print(ans)
# for i in range(3):
# 	print(*dist[i][:3])