//i2c Slave1, address 5
#include <Wire.h>

void setup() {
 Wire.begin(5);  //specifying that this board is address 5
 Wire.onReceive(receiveEvent);
 pinMode(13, OUTPUT);
 digitalWrite(13,LOW);
}

void loop() {
 }
 void receiveEvent (int howMany)
 {
  while(Wire.available())
  {
    char c = Wire.read();
  if(c == 'H')
  {digitalWrite(13, HIGH);
    }
    
    else if(c == 'L')
    {
      digitalWrite(13, LOW);
    }
  }
 }