mod = 998244353
h,w,k = map(int,input().split())
a = [[0] * w for i in range(h)]
for i in range(k):
	x,y,v = map(int,input().split())
	a[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 = (ans + a[x][y]) % mod

print(ans)