exit status 1 'FF62D' was not declared in this scope

here is my code and i have an error

char Forwardcode = FF62D;
char Rightcode = FFC23D;
char Leftcode = FF22DD;

void ArretMTR() {
  digitalWrite(MTR_right,LOW);
  digitalWrite(MTR_left,LOW);
}


IRrecv irrecv(RECV_PIN);
decode_results results; //La classe decode_results est définie dans IRremote.h


void setup() 
{
 Serial.begin (9600);
 irrecv.enableIRIn(); // Démarrez le récepteur
 digitalWrite(MTR_right,LOW);
 digitalWrite(MTR_left,LOW);

  }
void loop() {

  
 if (irrecv.decode(&results)) {
   Serial.println(results.value, HEX); 
    irrecv.resume(); // Recevez la prochaine valeur
  }
  delay (100); // petit délai pour éviter les erreurs de lecture

 if (Serial.available())//lire les résultat
  {
    RV = Serial.read();
    if (RV == Forwardcode )//vérifier pour avancer
    {
      Serial.print("avant !");
      digitalWrite(MTR_right,HIGH);
      digitalWrite(MTR_left,HIGH);
    }
    if (RV == Rightcode)//vérifier pour tourner vers la droite
    {
       digitalWrite(MTR_right,LOW);
       digitalWrite(MTR_left,HIGH);
       Serial.print("droite !");
       delay(750);
       digitalWrite(MTR_right,LOW);
       digitalWrite(MTR_left,LOW);
    }
    if (RV == Leftcode)//vérifier pour tourner vers la gauche
    {
       digitalWrite(MTR_right,HIGH);
       digitalWrite(MTR_left,LOW);
       Serial.print("gauche !");
       delay(750);
       digitalWrite(MTR_right,LOW);
       digitalWrite(MTR_left,LOW);
    }
  }
}

and here is error

voitureRC_IR:7:20: error: 'FF62D' was not declared in this scope
 char Forwardcode = FF62D;
                    ^~~~~
voitureRC_IR:8:18: error: 'FFC23D' was not declared in this scope
 char Rightcode = FFC23D;
                  ^~~~~~
C:\Users\Utilisateur\Desktop\Lilian\code\projarduino\voitureRC_IR\voitureRC_IR.ino:8:18: note: suggested alternative: 'FOC2A'
 char Rightcode = FFC23D;
                  ^~~~~~
                  FOC2A
voitureRC_IR:9:17: error: 'FF22DD' was not declared in this scope
 char Leftcode = FF22DD;
                 ^~~~~~
exit status 1
'FF62D' was not declared in this scope

thanks for help (if you can speak french it's good beacause i'm french)

What do you think FF62D is ?

You’ve confused IR codes with character codes.
Presumably you trying to convert a sketch that used to work with IR to work with serial input instead?

char Forwardcode = 'A';
char Rightcode ='D';
char Leftcode = 'G';