int led=13;
int st=0;
int button=0;
void setup() {
  // put your setup code here, to run once:
  pinMode(led,OUTPUT);
  pinMode(2,INPUT);
digitalWrite(13,LOW);
}

void loop() {
  // put your main code here, to run repeatedly:
button = digitalRead(2);
if(button){
  delay(100);
  st = 1;
  while(st){
    digitalWrite(led,HIGH);
    button = digitalRead(2);
    delay(10);
    if(button){
      st = 0;
    }
  }
  digitalWrite(led,LOW);
}else{

  digitalWrite(led,LOW);
  delay(10);
}
}