h,w,k = map(int,input().split())
masu = [[0]*(w) for i in range(h)]
for i in range(k):
  x,y,v = map(int,input().split())
  masu[x-1][y-1] = v

mod = 998244353
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 += masu[x][y]
          ans %= mod

print(ans)