main()
{

    int n;
    scanf("%d",&n);
    if(n%2=0)            //if(n%2==0)
         printf("该数是偶数!\n");
    else
         printf("该数是奇数!\n");

}

main()
{

    int x,y;
    scanf("%d",&x);
    if(x<0)
       y=0;
    else if(x<10) 
       y=2+x;
    else (x<20)      //  else if(x<20)
       y=3*x;
    else
       y=x;
    printf("%d\n",y);

}

main()
{

    int n;
    scanf("%d",&n);
    if(n%2==0)
         printf("该数是偶数!\n");
    else
         printf("该数是奇数!\n");

}