# 讀數據到數組中defreadToArray():
s =input()
nums = s.strip().split()
nums =[int(num)for num in nums]return nums
n,m,k = readToArray()[0:3]
arr =[[0for i inrange(n+5)]for i inrange(n+5)]# 根據火把修改位置defmodifyFire(x,y):for i inrange(-1,2):for j inrange(-1,2):
nx = x+i
ny = y+j
if nx>0and nx<=n and ny >0and ny <= n:
arr[nx][ny]=1# 修改值# 修改零散點if y -2>0:
arr[x][y-2]=1if x-2>0:
arr[x-2][y]=1if x+2<= n:
arr[x+2][y]=1if y+2<= n :
arr[x][y+2]=1defmodifyStone(x,y):for i inrange(-2,3):for j inrange(-2,3):
nx = x + i
ny = y + j
if nx >0and nx <= n and ny >0and ny <= n:
arr[nx][ny]=1# 修改值#輸入火把for i inrange(m):
x,y = readToArray()[0:2]# 根據火把的位置遍歷去修改數組
modifyFire(x,y)for i inrange(k):
x,y = readToArray()[0:2]
modifyStone(x,y)
cnt =0for i inrange(1,n+1):for j inrange(1,n+1):if arr[i][j]==0:
cnt+=1print(cnt)