Array Search Loop Logic

The following code segment is intended to find the first occurrence of the value 3 in the array arr. Which statement should replace // missing line so that the code works as intended?

public class Search {
    public static void main(String[] args) {
        int[] arr = {1, 2, 3, 4, 5};
        int index = 0;
        while (index < arr.length && arr[index] != 3) {
            // missing line
        }
        if (index < arr.length) {
            System.out.println("Found 3 at index " + index);
        } else {
            System.out.println("3 not found");
        }
    }
}