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
res=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:
     res=(res+a[x][y])%mod
print(res)