const byte Ledpin = 13;
const byte Ledpin2 = 4;
const byte interruptPin = 3;
const byte interruptPin2 = 2;
byte check = 0;

void setup() {
  pinMode(Ledpin, OUTPUT);
  pinMode(Ledpin2, OUTPUT);
  pinMode(interruptPin, INPUT);
  pinMode(interruptPin2, INPUT);
  attachInterrupt(digitalPinToInterrupt(interruptPin), rood, CHANGE);
  attachInterrupt(digitalPinToInterrupt(interruptPin2), groen, CHANGE);
}

void loop() {
  if(check == 1){
    digitalWrite(Ledpin, HIGH);
    digitalWrite(Ledpin2, LOW);
  }
  else if(check == 2){
    digitalWrite(Ledpin, LOW);
    digitalWrite(Ledpin2, HIGH);    
  }
  else{
    digitalWrite(Ledpin, LOW);
    digitalWrite(Ledpin2, LOW);        
  }
}

void rood() {
  if(check==0){
    check = 1;
  }
}

void groen() {
  if(check==0){
    check = 2;
  } 
}