Bus

function bus(input) {
    let passengers = Number(input[0]);
    let stations = Number(input[1]);
    let index = 2;

    for (let i = 1; i <= stations; i++) {
        let outputPassengers = Number(input[index++]);
        let inputPassengers = Number(input[index++]);

        passengers += inputPassengers - outputPassengers;

        if (i % 2 == 1) {
            passengers += 2;
        } else {
            passengers -= 2;
        }
    }

    console.log(`The final number of passengers is : ${passengers}`);
    return;
}