#include<stdio.h>
int main()
{
    double x,y;
    printf("请输入X的值\n");
    scanf("%f",&x);   
    if(x<10)
    {   
        if(x<1)
            printf("%f\n",x);
        else   
            y=2*x-1;
            printf("%f\n",y);
    }
        else
        y=3*x-11;
        printf("%f\n",y);
    return 0;
}