#define LED   2
#define PUSH  3

void setup() {
  // put your setup code here, to run once:
  pinMode(LED, OUTPUT);
  pinMode(PUSH, INPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  if(digitalRead(PUSH) == 0){
    digitalWrite(LED, HIGH);
  }
  else{
    digitalWrite(LED, LOW);
  }
  delay(1); // this speeds up the simulation
}