h, w, k = map(int, input().split())
G = [[0 for _ in range(w)] for _ in range(h)]
for _ in range(k):
    x, y, v = map(int, input().split())
    G[x - 1][y - 1] += v
mod = 998244353

ans = 0
for i in range(h):
    for j in range(w):
        t = i - j
        for x in range(h):
            for y in range(0, min(x - t + 1, w)):
                if x + y >= i + j:
                    ans += G[x][y]
                    ans %= mod
print(ans)