def main():
    H, W, K = map(int, input().split())
    assert(1 <= H and H <= 100000)
    assert(1 <= W and W <= 100000)
    assert(0 <= K and K <= min(H*W, 200000))

    grid = [[0 for _ in range(W)] for _ in range(H)]
    XYVs = [None for _ in range(K)]
    for i in range(K):
        X, Y, V = map(int, input().split())
        assert(1 <= X and X <= H)
        assert(1 <= Y and Y <= W)
        assert(0 <= V and V <= 1000000000)
        X -= 1
        Y -= 1
        XYVs[i] = (X, Y, V)
        grid[X][Y] = V

    ans = 0
    for i in range(H):
        for j in range(W):
            for x in range(H):
                for y in range(W):
                    if x+y >= i+j and x-y >= i-j:
                        ans += grid[x][y]
    print(ans % 998244353)


if __name__ == '__main__':
    main()