int x;          
int y;            
bool OF= 0; 
int ON = HIGH; 

void setup() {
  pinMode(5, INPUT_PULLUP); 
  pinMode(2, OUTPUT);      
  Serial.begin(9600);      
}

void loop() {
  x = digitalRead(5);       
  y = OF ? HIGH : LOW; 

  
  if (ON == HIGH && x == LOW) {
    OF = !OF;                
    digitalWrite(2, OF ? HIGH : LOW);



  
  }

  ON = x;