H,W,K = map(int,input().split())
dat = [[0] * W for _ in range(H)]
for _ in range(K):
    x,y,v = map(int,input().split())
    dat[x-1][y-1] = v
ans = 0
P = 998244353

for i in range(H):
    for j in range(W):
        for x in range(i,H):
            for y in range(W):
                if x + y >= i + j and x - y >= i - j:
                    ans += dat[x][y]
        ans %= P
print(ans)