
void main()
{
	int a[400]={0};
	int m,n,i,out,sum;

	while(1){
		scanf("%d %d",&n,&m);
		if(m==0&&n==0) break;
		out=m;
		sum=n;
		for(i=1;i<=n;i++) a[i]=1;
		for(i=1;sum>1;){
			
			if(a[i]==0){
				i++;
				if(i>n) i=1;
				continue;
			}
			else out--;
			if(out==0){
				a[i]=0;
				sum--;
				out=m;
			}
			i++;
			if(i>n) i=1;
		}
		for(i=1;i<=n;i++) if(a[i]==1) break;
		printf("%d\n",i);
	}
}
