// C++ code
//

int a = 0;

void setup()
{
	DDRD = 0b11100000;
}

void red()
{
    PORTD = 0b10000000;
    a=1;
}

void yellow()
{
    PORTD = 0b01000000;
    a=2;
}

void green()
{
    PORTD =  0b00100000;
}
 


void loop()
{
  if (a == 0){
    attachInterrupt(digitalPinToInterrupt(2),red,HIGH);
  }
  delay(200);
  if (a == 1){
    attachInterrupt(digitalPinToInterrupt(2),yellow,HIGH);
  }
  delay(200);
  if (a == 2){
    attachInterrupt(digitalPinToInterrupt(2),green,HIGH);
  }
}