#include<SoftwareSerial.h>
void setup() {
pinMode(PA6, OUTPUT); //initializing led1
pinMode(PA2, OUTPUT); //initializing led2
Serial.begin(9600);
}

void loop() {
  
 if (Serial.available() == 0) {
digitalWrite(PA6, HIGH); 
digitalWrite(PA2, LOW);
 }
 if (Serial.available() == 1) {
digitalWrite(PA6, LOW); 
digitalWrite(PA2, HIGH); 
 }
 
}