char n[10]={0,1,3,7,15,31,63},i;

void main()
{
trisa=0;trisb=0b11000000;portb=0;porta=0;
loop:
while(portb.f6==0 && i<6)
                       {
                       i++;
                       portb=n[i];
                       if(i==2)porta=0b10101;
                       else porta=0;
                       delay_ms(500);
                       }
while(portb.f7==0 && i>0)
                       {
                       i--;
                       portb=n[i];
                       if(i==2)porta=0b10101;
                       else porta=0;
                       delay_ms(500);
                       }
goto loop;

}