($Aw,$Ab)=glob<>;
($Bw,$Bb)=glob<>;
($C,$D)=glob<>;
if($Ab<$C){
	$Aw-=$C-$Ab;
	$Bw+=$C-$Ab
}
if($Bw<$D){
	$Aw+=$Bw
}else{
	$Aw+=$D
}
print$Aw