String receivedMessage; 
void setup() 
{
 Serial.begin(9600); 
}
void loop() 
{
 if (Serial.available() > 0) 
 {
   receivedMessage = Serial.readString(); 
   Serial.print("Received Message: ");
   Serial.println(receivedMessage); 
   delay(1000); 
   Serial.print("Response: ");
   Serial.println("Acknowledged!"); 
 }
}