import java.util.Scanner;
public class Main {
public static int flag[]=new int[305];
public static void init(){
for(int i=0;i<305;i++){
flag[i]=0;
}
}
public static void main(String[] args){
Scanner sc=new Scanner(System.in);
int n,m;
n=sc.nextInt();
m=sc.nextInt();
while(n!=0 && m!=0){
int index=-1;
int count=0;
init();
for(int i=1;i<n;i++){
count=0;
while(count!=m){
index=(index+1)%n;
if(flag[index]==0){
count++;
if(count==m){
flag[index]=1;
}
}
}
}
for(int j=0;j<n;j++){
if(flag[j]==0){
System.out.println(j+1);
break;
}
}
n=sc.nextInt();
m=sc.nextInt();
}
}
}