local h, w, k = io.read("*n", "*n", "*n")
local t = {}
for i = 1, h do
  t[i] = {}
  for j = 1, w do
    t[i][j] = 0
  end
end
for i = 1, k do
  local x, y, v = io.read("*n", "*n", "*n")
  t[x][y] = v
end
local mod = 998244353
local function badd(x, y) return (x + y) % mod end
local ans = 0
for i = 1, h do for j = 1, w do
  for x = 1, h do for y = 1, w do
    if i + j <= x + y and i - j <= x - y then
      ans = badd(ans, t[x][y])
    end
  end end
end end
print(ans)