Bus

function Bus(input){
    let Passagers = Number(input.shift());
    let stops = Number(input.shift());

    for(let i = 1; i <= stops; i++ ){
      let exitPeople = Number(input.shift());
      let enterPeople = Number(input.shift());

      Passagers -= exitPeople;
      Passagers += enterPeople;

       if(i % 2 === 0){
         Passagers -= 2;


       }else{
         Passagers += 2;
       }
    }
    console.log(`The final number of passengers is : ${Passagers}`);
}
Bus([20,2,10,5,5,3]);