/*??????????????????????n????m??????????m%(n-1)????0----n-1????????????m%(n-1)+1??????????????????????n-1????m???????n-1??????s??????????n??????(s+m)%i??????,?????????????????????*/

int main() {
    int n, m, i, s, j, counter=0;
    int answer[200];
    for (;;){
        scanf("%d%d", &n, &m);     
        if (n==0&&m==0) break;
        s=0;
        for (i=2; i<=n; i++) {     
           s=(s+m)%i;
        }
            answer[counter]=s+1;
            counter+=1;
    }
    for (j=0;j<counter;j++) {
        printf ("%d\n", answer[j]);
    }
    return 0;
}