h,w,k=map(int,input().split())
ms=[[0]*54 for _ in range(54)]
h+=1
w+=1
for _ in range(k):
	y,x,v=map(int,input().split())
	ms[y][x]=v
for x in range(1,w):
	s=0
	for y in range(h,0,-1):
		s+=ms[y][x]
		ms[y][x]=s
ans=0
for i in range(1,h):
	for j in range(1,w):
		for x in range(1,w):
			y=i+abs(j-x)
			if(1<=y and y<=h):ans+=ms[y][x]
print(ans%998244353)