mod = 998244353

H,W,K = map(int, input().split())
S = [[0]*W for _ in range(H)]

for i in range(K):
    x, y, v = map(int, input().split())
    S[x-1][y-1] = v

ans1=0
for i in range(H):
    for j in range(W):
        ans2 = 0
        for x in range(H):
            for y in range(W):
                if x+y >= i+j and x-y >= i-j:
                    ans2+=S[x][y]
        ans1 += ans2
print(ans1%mod)