public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner in = new Scanner(System.in);
int t = in.nextInt();
TreeMap<Long, Long> tmap = new TreeMap<>();
long res = 0;
while (t-- > 0) {
res = 0;
int n = in.nextInt();
long m = in.nextLong();
tmap.clear();
long[] arr = new long[n];
res = in.nextLong();
arr[0] = res % m;
res = Long.MIN_VALUE;
tmap.put(arr[0], arr[0]);
for (int i = 1; i < arr.length; i++) {
arr[i] = in.nextLong();
arr[i] %= m;
arr[i] += arr[i - 1];
arr[i] %= m;
if (tmap.higherEntry(arr[i]) == null) {
res = Math.max(res, arr[i]);
tmap.put(arr[i], arr[i]);
continue;
}
long val = tmap.higherEntry(arr[i]).getValue();
res = Math.max(res, (arr[i] - val + m) % m);
tmap.put(arr[i], arr[i]);
}
System.out.println(res);
}
}
