int count = 0;
void setup() {
  // put your setup code here, to run once:
Serial.begin(115200);
pinMode(11, INPUT);
pinMode(2, INPUT);
pinMode(3, OUTPUT);
pinMode(4, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:

 Serial.println("Total Passengers = ");
  Serial.println(count);
  delay(100);

 if(digitalRead(11) == HIGH){
    count++;
  }
 else {
  count = count;
 }
 if(digitalRead(2) == HIGH){
  count--;
 }
 else{
  count = count;
 }

 if(count > 10){
  digitalWrite(3, HIGH);
Serial.println("Warning! Limit Exceeded!");
  digitalWrite(4, LOW);
 }
 else{
  digitalWrite(3, LOW);
  digitalWrite(4, HIGH);
  count = count;
}

}