member = []
for _ in range(int(input())):
    a, b = map(int, input().split())
    member.append([a, b])
item = []
for _ in range(int(input())):
    a, b = map(int, input().split())
    item.append([a, b])
count = 0
for [a, b] in member:
    for [x, y] in item:
        if a <= x and b >= y:
            count += 1
print(count)