int main()
{
   int n,m,s,i;
   
   scanf("%d %d",&n,&m);
   while(n!=0)
   {
            
              s=0;
              for(i=2;i<=n;i++)
              s=(s+m)%i;
              printf("%d\n",s+1);
              scanf("%d %d",&n,&m);
              }
              

   
             getchar();getchar();getchar();
             }
