 
void main()
{
     int g(int m,int s,int t);        /*????*/
     void f(int a[],int k,int t);         /*????*/
     int a[301]={0},b[301]={0},c[100][2]={0},m,n,t,k,j,i=0;  /*???a???????k????????*/
     do
     {
         scanf("%d %d",&c[i][0],&c[i][1]);         /*????????????c[100][2]?*/
         i++;
     }while(c[i-1][0]!=0);       /*?????????*/
     k=i-1;                           /*k?????????*/
     for(j=1;j<=k;j++)
     {
         n=c[j-1][0];m=c[j-1][1];
         for(i=0;i<300;i++)
         {a[i]=0;b[i]=0;}            /*????a?b??*/
         for(i=0;i<=n-1;i++)
         {
              a[i]=i+1;              /*???a????????????*/
         }
         t=n;i=0;                    /*?t?????????*/
         while(a[1]!=0)                   /*?a[1]==0???????????a[0]???*/
         {
              f(a,g(m,b[i],t),t);
              i++;
              if(g(m,b[i-1],t)==(t-1)/*??????????????*/)                           
                   b[i]=0;/*????a[0]????????*/
              else
                   b[i]=g(m,b[i-1],t);
              t--;
         }
         if(j<k)
              printf("%d\n",a[0]);
         else
              printf("%d",a[0]);
     }
}
 
int g(int m,int s,int t)         /*??g??????m??a[s]???????t???????????c???????????????*/
{
     int c;
     if((s+m)%t==0)
         c=t-1;
     else
         c=(s+m)%t-1;
     return c;
}
 
void f(int a[],int k,int t)      /*??f??????m???????a[k])?????a[c]=a[c+1];a[c+1]=a[c+2];a[c+2]=a[c+3];??  a[t-1]=a[t]=0?t??????k???????????*/
{
     int i;
     for(i=k;i<=t;i++)
     {
         a[i]=a[i+1];
     }
}