int lampa=9;
int knopka=2;
boolean knopka1, knopka0;
int num=0;
void setup() {
  pinMode(lampa, OUTPUT);
  pinMode(knopka, INPUT);
}
void loop() {
  knopka1 = digitalRead(knopka);
  if (knopka1 == HIGH && knopka0 == LOW) {
    num=num+1;
    delay(100);
  }
  else{
    delay(50);
  }
  knopka0 = knopka1;
  if(num%2==1){
    digitalWrite(lampa, HIGH);
  }
  if(num%2==0){
    digitalWrite(lampa, LOW);
  }
}