mod = 998244353


def main():
    import sys
    input = sys.stdin.readline

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

    ans = 0
    for h0 in range(H):
        for w0 in range(W):
            for h in range(H):
                for w in range(W):
                    if h + w >= h0 + w0 and h - w >= h0 - w0:
                        ans += G[h][w]
                        ans %= mod
    print(ans)


if __name__ == '__main__':
    main()