MOD = 998244353
H,W,K = map(int,input().split())

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

res = 0
for i in range(H):
    for j in range(W):
        for y in range(H):
            for x in range(W):
                if (y+x >= i+j) and (y-x) >= (i-j):
                    res += G[y][x]
                    res %= MOD

print(res)