package main

import . "fmt"

func main() {
	var h,w,k int
	Scan(&h,&w,&k)
	f:=make([][]int64,h+1)
	for x:=range f {
		f[x]=make([]int64,w+1)
	}
	for ;k>0;k-- {
		var x,y int
		var v int64
		Scan(&x,&y,&v)
		f[x][y]=v
	}
	var a int64
	const m=998244353
	for i:=1;i<=h;i++ {
		for j:=1;j<=w;j++ {
			for x:=1;x<=h;x++ {
				for y:=1;y<=w;y++ {
					if x+y>=i+j&&x-y>=i-j {
						a=(a+f[x][y])%m
					}
				}
			}
		}
	}
	Println(a)
}