K=-1
a=0
while K:
	i,j,v=map(int,input().split())
	if K<0:H,W,K=i,j,v
	else:
		l,r,K=i-j,i+j-W-1,K-1
		a+=(i*i-((l>0)*(l+1)*l+(r>0)*(r+1)*r)//2)*v
print(a%998244353)