int ledGreen = 7, ledBlue = 6, ledRed = 5, pb = 3;
int state = 4;


void setup(){
Serial.begin(9600);
pinMode(ledGreen, OUTPUT);
pinMode(ledBlue, OUTPUT);
pinMode(ledRed, OUTPUT);
pinMode(pb, INPUT);
}

void loop(){
int status = digitalRead(pb);

if (status == HIGH){
 state--;
 Serial.println("state=  ");
 Serial.println(state);
 delay(100);
} 
if (state == 1){
digitalWrite(ledGreen, HIGH);
delay(100);
}
else if (state == 2){
  digitalWrite(ledBlue, HIGH);
  delay(100);
}
else if(state == 3){
  digitalWrite(ledRed, HIGH);
  delay(100);
}
else if(state == 0){
  digitalWrite(ledGreen, LOW);
  digitalWrite(ledBlue, LOW);
  digitalWrite(ledRed, LOW);
  state = 4;
  delay(100);}

/*
else{
  digitalWrite(ledGreen, LOW);
  digitalWrite(ledBlue, LOW);
  digitalWrite(ledRed, LOW);
}  */
}