Switch case not being entered in JAVA

I'm having a task to solve in which I have to find the biggest sum between the digits of 3nums integer.

I've decided to do it with "switch case", because I am still a newbie. But, unfortunately when I run it, it skips directly out after the loop. Here's my code:

import java.util.Scanner;

public class Game {


    public static void main(String[] args) {

        Scanner scanner = new Scanner(System.in);
        String input = scanner.nextLine();
        int nums = Integer.parseInt(input);
        int firstNum, secondNum, thirdNum, sumNums, sumNums2 = 0;

        firstNum = Character.getNumericValue(input.charAt(0));
        secondNum = Character.getNumericValue(input.charAt(1));
        thirdNum = Character.getNumericValue(input.charAt(2));

        switch (nums) {
            case 1:
                sumNums = firstNum + secondNum + thirdNum;
                sumNums2 = sumNums;
            case 2:
                sumNums = firstNum + secondNum * thirdNum;
                if (sumNums > sumNums2) {
                    sumNums2 = sumNums;
                }
            case 3:
                sumNums = firstNum * secondNum + thirdNum;
                if (sumNums > sumNums2) {
                    sumNums2 = sumNums;
                }
            case 4:
                sumNums = firstNum * thirdNum + secondNum;
                if (sumNums > sumNums2) {
                    sumNums2 = sumNums;
                }
            case 5:
                sumNums = firstNum * secondNum * thirdNum;
                if (sumNums > sumNums2) {
                    sumNums2 = sumNums;
                    break;
                }
        }
        System.out.println(sumNums2);
    }
}

Thanks in advance!