import sys
#sys.setrecursionlimit(n)
import heapq
import re
import bisect
import random
import math
import itertools
from collections import defaultdict, deque
from copy import deepcopy

w = int(input())
h = int(input())
n = int(input())
r = defaultdict(list)
for i in range(n):
  a,b = input().split()
  r[a].append(b)
c = defaultdict(int)
count = len(r) * h
for rr in r:
  for i in r[rr]:
    count -= 1
    c[i] = 1
count += (w - len(r)) * len(c)
print(count)