h, w, k = map(int, input().split())
mod = 998244353
ls = [list(map(int, input().split())) for _ in range(k)]
g = [[0] * w for _ in range(h)]
for x, y, v in ls:
  g[x-1][y-1] = 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 += g[x][y]
print(ans % mod)