package test;

import java.math.BigInteger;
import java.util.Scanner;

public class Main {
	public static BigInteger dp[][] = new BigInteger[28][111];
	public static String str[]= new String[]{"ACM-ICPC",
	"BIDU",
	"consonant:BCDFGHJKLMNPQRSTVXZWY",
	"D41D8CD98F00B204E9800998ECF8427E",
	"2.718281828459...",
	"0xFACEB00C",
	"1E100.net",
	"\\Huge{String}",
	"InternationalCollegiateProgrammingContest",
	"JinKeLa",
	"KeepItSimpleStupid",
	"1000mL",
	"Micro$oftCorp",
	"",
	"Oops",
	"pneumonoultramicroscopicsilicovolcanoconiosis",
	"A",
	"P",
	"M",
	"TheQuickBrownFoxJumpsOverTheLazyDog",
	"\\bigcup",
	"vowel:AEIOU",
	"WWW",
	"X-ray",
	"YOOOOOO!",
	"ZheJiangUniversity"};	
	static int N,M;
	static BigInteger K;
	
	public static void gao(String s, int dep){
		
		for (int i=0;i<s.length();i++){
			BigInteger now = K;
			char c = s.charAt(i);
			
			if (dep>0 && c>='A' && c<='Z') 
				now = now.subtract(dp[c-'A'][dep-1]);
			else now = now.subtract(BigInteger.ONE);
			//System.out.println(now+" "+c);
			if (now.compareTo(BigInteger.ZERO)<0){
				if (dep>0 && c>='A' && c<='Z') gao(str[c-'A'],dep-1);
				else{
					System.out.print(c);
					M--;
				}
				if (M==0) return ;
			}else K=now;
			
			
		}
	}
	
	public static void main(String[] args) {
		// TODO Auto-generated method stub

		Scanner readin = new Scanner(System.in);

		for (int i=0;i<26;i++)
			dp[i][0] = BigInteger.valueOf(str[i].length());
		//for (int i=0;i<26;i++)System.out.print(dp[i][0]+" ");
		//System.out.println();
		for (int i = 1; i <= 101; i ++){
			for (int j=0; j<26;j++){
				dp[j][i]=BigInteger.ZERO;
				for (int l=0;l<str[j].length();l++)
					if (str[j].charAt(l)<='Z' && str[j].charAt(l)>='A'){
						int x = str[j].charAt(l)-'A';
						dp[j][i] = dp[j][i].add(dp[x][i-1]);
					}else dp[j][i] = dp[j][i].add(BigInteger.ONE);
				//if (i==1) System.out.print(dp[j][1]+" ");
				
			}
			//if (i==1) System.out.println();
		}
	
	
		while (readin.hasNextLine()){	
			String st = readin.nextLine();
			//System.out.println(st);
			N = readin.nextInt();
			M = readin.nextInt();
			K = readin.nextBigInteger();
			readin.nextLine();
			//System.out.println(N+" "+M+" "+K);
			gao(st,N);
			System.out.println();
		}

		
	}

}