void setup()
{
  volatile char *dirf,*outf;
  volatile char *dirk,*outk;
  volatile char *dira,*outa;
  volatile char *dirc,*outc;
  dirf=0x30; outf=0x31;
  dirk=0x107; outk=0x108;
  dira=0x21; outa=0x22;
  dirc=0x27; outc=0x28;
  *dirf=0xFF; *dirk=0xFF;
  *dira=0xFF; *dirc=0xFF;
  volatile long arr[]={0x3F,0x06,0x5B,0x4F,0x66,0x6D,0x7D,0x07,0x7F,0x6F};
  volatile long i,j,k,l,m,prime=1;
  while(1)
  {
  for(i=0;i<=9;i++)
  {
    for(j=0;j<=9;j++)
    {
      prime=1;
      l=10*i+j;
      if(l==0) prime=0;
      for(m=2;m<l-1;m++)
      {
        if(l%m==0)
        {
          prime=0;
          break;
        }
      }
      if(prime==1 && l>10)
      {
        *outa=arr[i];
        *outc=arr[j];
        for(k=0;k<=200000;k++);
      }
      else if(prime==1 && l<10){
        *outa=0;
        *outc=arr[j];
        for(k=0;k<=200000;k++);
      }
    }
  }
}
}

void loop()
{
  
}