#include <Wire.h>

int led1 = 2;                
int led2 = 3;
int led3 = 4;
int led4 = 5;
int y=0;

void setup()
{
  Wire.begin(4);                // join i2c bus with address #4
  Wire.onReceive(receiveEvent); // register event
  Serial.begin(9600);           // start serial for output

  pinMode (led1, OUTPUT);
  pinMode (led2, OUTPUT);
  pinMode (led3, OUTPUT);
  pinMode (led4, OUTPUT);
}


void receiveEvent(int howMany)
{
 
  y = Wire.read();    // receive byte as an integer

  
}

void loop()
{
  delay(50);
if (y == 1)                                    
  {
    digitalWrite(led1, HIGH);
    digitalWrite(led2, HIGH);
    digitalWrite(led3, HIGH);
    digitalWrite(led4, HIGH);
  }
  
  else
  {
    digitalWrite(led1, LOW);
    digitalWrite(led2, LOW);
    digitalWrite(led3, LOW);
    digitalWrite(led4, LOW);
  }

}