Bus

package main

import "fmt"

func main() {
    var passengers, stations, outputPassengers, inputPassengers int
    fmt.Scanln(&passengers)
    fmt.Scanln(&stations)

    for i := 1; i <= stations; i++ {
        fmt.Scanln(&outputPassengers)
        fmt.Scanln(&inputPassengers)
        passengers += inputPassengers - outputPassengers

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

    fmt.Printf("The final number of passengers is : %d", passengers)
}