#include<LiquidCrystal.h>
LiquidCrystal lcd(12,11,10,9,8,7);
int a,b,c;
void setup()
{
  lcd.begin(16,2);
  pinMode(6,INPUT_PULLUP);
  pinMode(5,INPUT_PULLUP);
  pinMode(4,INPUT_PULLUP);
  //pinMode(6, OUTPUT);
  //lcd.print("hello students");
  a=b=c=0;
}
void loop()
{
 if(digitalRead(6)==LOW){
  a=1;
  lcd.clear();
  lcd.print(a);
  //delay(1000);
 }
 if(digitalRead(5)==LOW){
  b=a;
  lcd.clear();
  //lcd.print(b);
  //delay(1000);
 }
 if(digitalRead(4)==LOW){
  c=a+b;
  lcd.clear();
  lcd.print(c);
  a=c;
 }
 delay(150);
}