w,h = map(int,input().split())
n = int(input())
row = [0,h]
column = [0,w]
for i in range(n):
a,b = map(int,input().split())
if a == 0:
row.append(b)
else:
column.append(b)
row.sort()
column.sort()
# print(row)
# print(column)
ans = 0
for i in range(1,len(row)):
for j in range(1,len(column)):
S = (row[i] - row[i-1]) * (column[j] - column[j-1])
if S > ans:
ans = S
print(ans)