int main ()
{int n=1,m=1,king=0,left=0,count=0;
for (int i1=0;n!=0&&m!=0;i1++)
{  count=0;
int houzi[300];
    scanf ("%d%d\n",&n,&m);
    if (n==0&&m==0) {break;}
    left=n;
    for (int i2=0;i2<n;i2++)
    {
        houzi[i2]=1;
    }
    for (int i3=0;left!=1;i3++)
    {        if (i3>n-1) {i3=i3%(n);}
        if (houzi[i3]==0)
        {
            continue;
        }
        count++;

        if (count==m) {houzi[i3]=0;left--;count = 0;}
        if (count>m) {count=count%m;}       
    }
    for (int i4=0;i4<n;i4++)
    {
        if (houzi[i4]==1) {king=i4+1;break;}
    }
    printf("%d\n",king);
}
    return 0;
}