H,W,K=map(int, input().split())
mod=998244353 
A=[[0]*W for _ in range(H)]
for i in range(K):
  x,y,v=map(int, input().split())
  x-=1
  y-=1
  A[x][y]=v 
ans=0
for h in range(H):
  for w in range(W):
    for hh in range(H):
      for ww in range(W):
        if hh+ww>=h+w and hh-ww>=h-w:
          ans+=A[hh][ww]
          ans%=mod
print(ans)