Set the digits in the number in needed place

It is necessary to set the digits in the number in their place so in the end you get the highest number. (ex. 58734 - to become 87543).

In this case, I took a three-digit number, but is there a better, cleaner code, more reasonable? Do I have to write so many if conditions if I have numbers with multiple digits like 58734 in the example?

Here's my code:

    Scanner sc = new Scanner(System.in);

    System.out.print("Enter 3-digit number: ");
    int num = sc.nextInt();
    while (num < 100 || num > 999) {
        System.out.print("Number isn't 3-digit! Enter it again: ");
        num = sc.nextInt();
    }
    int j = num % 10;
    int d = (num / 10);
    d = d % 10;
    int s = num / 100;

    if (j > d) {
        int t = j;
        j = d;
        d = t;
    }
    if (j > s) {
        int t = j;
        j = s;
        s = t;
    }
    if (d > s) {
        int t = d;
        d = s;
        s = t;
    }

    int res = s * 100 + d * 10 + j;
    System.out.println("Result: " + res);

Output:

Enter 3-digit number: 453
Result: 543