main()
{
    int x=1,y=0,a=0,b=0;
    switch (x)
    {
       case 1: switch(y)
               {
case 0 :a++;break;
case 1:b++;break;
               }
       case 2:a++;b++;break;
       case 3:a++;b++;
    }
    printf("a=%d,b=%d\n",a,b);
}