import java.util.Scanner;

class LianDemo1212 {
    public static void main(String[]args){
        Scanner sc=new Scanner(System.in);
        
        System.out.println("请输入一个数据");
        int x=sc.nextInt();
        int y;
        
        if(x>=3){
            y=x*2+1;
        }else if(-1<=x&&x<3){
            y=x*2;
        }else if(x<=-1){
            y=x*2-1;
        }
        System.out.println("y:"+y);//[b]显示这一行 可能尚未初始化变量y
    }
}