problems with Switch case and IR reciver

Hi guys!
I’m having trouble with my program. I want to do something with the input of my IR remote.
This is the code. I get the fault "

Arduino: 1.8.2 (Windows 10), Board:“Arduino/Genuino Uno”

C:\Users\Licht en Geluid\Documents\Arduino\sketch_jun01a\sketch_jun01a.ino: In function ‘void loop()’:

sketch_jun01a:28: error: ‘FF18E7’ was not declared in this scope

case FF18E7:

^

sketch_jun01a:32: error: ‘FF4AB5’ was not declared in this scope

case FF4AB5:

^

exit status 1
‘FF18E7’ was not declared in this scope

This report would have more information with
“Show verbose output during compilation”
option enabled in File → Preferences.

whats the problem???
thanks for helping!
greets Daniël
(here the code).

#include <IRremote.h>
int RECV_PIN = 11;
IRrecv irrecv(RECV_PIN);
decode_results results;


void setup() {
Serial.begin(9600);
irrecv.enableIRIn();
}

void loop() {
  y = 0;
  if (irrecv.decode(&results)) {
    Serial.println(results.value, HEX);
    irrecv.resume(); // Receive the next value

  }
 

  delay(100);
  
switch (results.value, HEX){
  case FF18E7:
  Serial.println("forward");

    break;
case FF4AB5:
  Serial.println("backward");

    break;
    
case FF10EF:
  Serial.println("left");

  break;

case FF5AA5:
  Serial.println("right");
  break;
}

}

  case 0xFF18E7:etc

AWOL:  case 0xFF18E7:

etc

I can upload it for now but i can't use it. the fault code is:

C:\Users\Licht en Geluid\Documents\Arduino\sketch_jun01a\sketch_jun01a.ino: In function 'void loop()':

C:\Users\Licht en Geluid\Documents\Arduino\sketch_jun01a\sketch_jun01a.ino:23:3: warning: overflow in implicit constant conversion [-Woverflow]

   case 0xFF18E7:

   ^

C:\Users\Licht en Geluid\Documents\Arduino\sketch_jun01a\sketch_jun01a.ino:27:1: warning: overflow in implicit constant conversion [-Woverflow]

 case 0xFF4AB5:

 ^
etc.

what do I have to do with this?

switch (results.value)  {