($X,$Y,$N,$F)=glob<>;
for$y(0..$Y){
	for$x(0..$X){
		$_[$y][$x]=$F*($x+$y)
	}
}
for(<>){
	($dx,$dy,$c)=glob;
	for$y(reverse 0..$Y){
		for$x(reverse 0..$X){
			$_[$y][$x]-=$-=$_[$y][$x]-($_[$y-$dy][$x-$dx]+$c)
		}
	}
}
print$_[$Y][$X]