Serial.read control LED flashing

int LEDpin = 7;
int lapse = 0;
int inputChar;
int inputNumber;

void setup() {
  Serial.begin(9600);
}


void loop() {
  inputNumber = 0;
  if (Serial.available()>0){
    delay(5);
    while (Serial.available()>0){
      inputChar = Serial.read();
      inputNumber = inputNumber*10 + (inputChar - '0');
    }
          lapse = inputNumber;
  }
   pinMode(LEDpin, OUTPUT);
   digitalWrite(LEDpin,HIGH);
   delay(lapse);
   digitalWrite(LEDpin,LOW);
   delay(lapse);
}