WeirdScript

import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class WeirdScript {
    private static char getChar(int key) {

        if(key <= 52) {
            if(key <= 26) {
                return (char) (key + 96);
            }
            return (char)(key + 38);
        } else {
            int division = key / 26;
            return getChar(division % 2 == 0 ? key % 26: key % (26 * (division - 1)));
        }
    }
    private static String getKey(int key) {
        StringBuilder sb = new StringBuilder();
        sb.append(getChar(key));
        sb.append(getChar(key));
        return sb.toString();

    }
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String key = getKey(Integer.parseInt(sc.nextLine()));
        StringBuilder sb = new StringBuilder();
        String line = sc.nextLine();
        while(!line.equals("End")) {
            sb.append(line);
            line = sc.nextLine();
        }
        String input = sb.toString();
        Matcher matcher = Pattern.compile("(" + key + ")(.{0,50}?)(\\1)").matcher(input);
        while(matcher.find()) {
            String lineToPrint = matcher.group(2);
            if(!lineToPrint.isEmpty()) {
                System.out.println(lineToPrint);
            }

        }
    }
}