unsigned long t1;

void setup() {
  pinMode(13, OUTPUT);
  pinMode(4, INPUT);

  t1=millis();

  digitalWrite(13, LOW);
}

void loop() {
  /*
  if((millis()-t1)>500){
    digitalWrite(13, !digitalRead(13));
    t1=millis();
  }
  */

  if((millis()-t1)>200){
    if(digitalRead(4)){
      digitalWrite(13, !digitalRead(13));
      t1=millis();
    }
  }
}