int blinkrate = 0;
int led = 2;
void setup() {
  // put your setup code here, to run once:
pinMode(led, OUTPUT);
Serial.begin(9600);
 Serial.print("hello\n");
}
void loop() {
 
  // put your main code here, to run repeatedly:
if(Serial.available()){

  char ch = Serial.read();
  if(ch >='0' && ch<='9'){

    blinkrate = (ch-'0');
    blinkrate = blinkrate*100;
  }
  Serial.print(ch);
}

digitalWrite(led, HIGH);
delay(blinkrate);
digitalWrite(led, LOW);
delay(blinkrate);
}