Life system

ok, in my game im setting it up where u got 4 lifes… with 5 HPs each… when u miss something u loose a life

ok right now im testing… jst got the 4 lifes… i just did it like u would a score

on main frame
lifes = 4;

then…
onClipEvent (enterFrame) {
if (this.hitTest(_root.Ground_MC)) {
_root.score = _root.score -=10;
_root.lifes = _root.lifes -=1
this.gotoAndStop(10);
}
}

then i put on the mainframe

if (lifes<1){
gotoAndStop(5)
}

it dnt work?