/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
    public static List<String> commonChars(String[] words) {
        int[] minFreq = new int[26];
        Arrays.fill(minFreq, Integer.MAX_VALUE);
 
        for (String word : words) {
            int[] freq = new int[26];
            for (char c : word.toCharArray()) {
                freq[c - 'a']++;
            }
 
            for (int i = 0; i < 26; i++) {
                minFreq[i] = Math.min(minFreq[i], freq[i]);
            }
        }
 
        List<String> result = new ArrayList<>();
        for (int i = 0; i < 26; i++) {
            for (int j = 0; j < minFreq[i]; j++) {
                result.add(String.valueOf((char) (i + 'a')));
            }
        }
 
        return result;
    }
 
    public static void main(String[] args) {
        String[] words = {"bella", "label", "roller"};
        System.out.println("Common characters: " + commonChars(words)); // Output: [e, l, l]
    }
}
 
 
 

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