```
public class Solution {
public int countArrangement(int N) {
return ca(N, new int[N+1]);
}
public int ca(int N, int[] res){
if(N==0) return 1;
int r = 0;
for(int i = 1; i< res.length; i++){
if(res[i] == 0){
if(N%i==0 || i%N==0){
res[i] = N;
r+= ca(N-1, res);
res[i] = 0;
}
}
}
return r;
}
}
```