ln=[]
card=[]
for i in range(3):
    ln.append(int(input()))
for i in range(ln[2]):
    card.append(list(map(int,input().split())))

exist=[[0 for i in range(ln[j]+1)] for j in range(2)]

for i in range(2):
    for j in range(ln[2]):
        if exist[i][card[j][i]]==0:
            exist[i][card[j][i]]=1
            
n=ln[0]-exist[0].count(1)
m=ln[1]-exist[1].count(1)
ans=(ln[0]*ln[1]-n*m)-ln[2]
print(ans)