void setup() 
{
  DDRB |= 1<<5;
  DDRB |= 1<<4;
}

void loop() 
{
  PORTB |= 1<<5;
  PORTB &= ~(1<<4);
  delay(500);
  PORTB |= 1<<4;
  PORTB &= ~(1<<5);
  delay(500);

}