int num_blinks;
int j;
String msg="Enter number of blinks:";
void setup() {
  // put your setup code here, to run once:
pinMode(13,OUTPUT);
Serial.begin(9600);
}

void loop() {
Serial.println(msg);
  // put your main code here, to run repeatedly:
while(Serial.available()==0){

}
num_blinks=Serial.parseInt();
Serial.println(num_blinks);
for(j=1;j<=num_blinks;j++){
  digitalWrite(13, HIGH);
  delay(500);
  digitalWrite(13, LOW);
  delay(500); 
}
}