int r = 25;
  int g = 26;

void setup() {
  // put your setup code here, to run once:
  
  Serial.begin(115200);
  pinMode(r, OUTPUT);
  pinMode(g, OUTPUT);
}

void loop() {

  digitalWrite(r, HIGH);
  delay(1000);
  digitalWrite(r, LOW);
  digitalWrite(g, HIGH);
  delay(1000);
  digitalWrite(g, LOW);
}