int value = 0;

void setup() {
 Serial.begin(115200);

}

void loop() {
  Serial.println("Enter your points");
  while (Serial.available() == 0){

  }
 int value = Serial.parseInt();
 Serial.print("value is ");
 Serial.println(value); 
   if(value >= 80)
   {
    Serial.println("A");
    digitalWrite(8, HIGH);
    digitalWrite(9, LOW);
    digitalWrite(10, LOW);
    digitalWrite(11, LOW);
    digitalWrite(12, LOW);
   }
   else if(value <80 && value>=70)
   {
    Serial.println("B");
    digitalWrite(8, LOW);
    digitalWrite(9, HIGH);
    digitalWrite(10, LOW);
    digitalWrite(11, LOW);
    digitalWrite(12, LOW);
   }
   else if(value <70 && value>=60 )
   {
    Serial.println("C");
     digitalWrite(8, LOW);
    digitalWrite(9, LOW);
    digitalWrite(10, HIGH);
    digitalWrite(11, LOW);
    digitalWrite(12, LOW);
   }
   else if(value <60 && value>=50 )
   {
    Serial.println("D");
     digitalWrite(8, LOW);
    digitalWrite(9, LOW);
    digitalWrite(10, LOW);
    digitalWrite(11, HIGH);
    digitalWrite(12, LOW);
   }
   else if(value < 50 )
   {
    Serial.println("F");
     digitalWrite(8, LOW);
    digitalWrite(9, LOW);
    digitalWrite(10, LOW);
    digitalWrite(11, LOW);
    digitalWrite(12, HIGH);
   }
}