#define SWout 4
#define SWin 2
  int lastState1 = HIGH;  int lastState2 = HIGH;  int Nop;  long Tin1=0;  long LTin1=0;
  long Tout1=0;  long LTout1=0;  long Tin2=0;  long Tout2=0;  unsigned long Stauts1;
  unsigned long LastStauts1;

void setup() {
  Serial.begin(115200);
  pinMode(SWout, INPUT_PULLUP);
  pinMode(SWin, INPUT_PULLUP);
             }
void loop()
{
  int value1 = digitalRead((SWin));
  if (lastState1 != value1)
  {
    lastState1 = value1;
      if (value1 == LOW)
     {
      Serial.println(" pressed_1");
      Tin1=millis();
      Serial.print("Tin1 first time during in = ");
      Serial.println(Tin1);
     }
  }
  int value2 = digitalRead((SWout));
  if (lastState2 != value2) 
  {
    lastState2 = value2;
     if (value2 == LOW)
     {
      Serial.println(" pressed_2");
      Tout1=millis();
      Serial.print("Tout1 first time during out = ");
      Serial.println(Tout1);
    }
  }
  
      if (LastStauts1 != (Tin1-Tout1))
      {
        LastStauts1 = (Tin1-Tout1);
        if((Tin1-Tout1)<0 ) 
        {
          Nop++;
          Serial.print("No. of Person in Room =");
          Serial.println(Nop);
        }
        
       }
      
//Tin1=Tin2=Tout1=Tout2=0;
}