#include <cstdio>
#include <cstring>
#include <ctime>
#include <algorithm>
#include <vector>

using namespace std;

#define MAXABC 10000
#define MAXK 10000

int main(void) {
    
    int values[0xff];
    char abc[10000], *word, maxchar, minchar;
    int n, k, temp = 0;
    
    FILE* in = fopen("nthword.in", "rt");
    fscanf(in, "%s\n", abc);
    fscanf(in, "%d %d", &k, &n);
    fclose(in);
    
    //printf("%s %d %d", abc, k, n);
    
    for(int ii = 0; ii < 0xff; ++ii) {
        values[ii] = -1;
    }
    // cab --> 2=0, 0=1, 1=2
    for(int ii = 0; ii < strlen(abc); ++ii) {
        values[abc[ii]] = ii;
    }
    
    minchar = abc[0];
    maxchar = abc[strlen(abc)-1];
    
    word = new char[k + 1];
    for(int ii = 0; ii < k; ++ii) {
        word[ii] = minchar;
    }
    word[k] = '\0';
    
    while(temp < n) {
        // get next word
        int x = k - 1;
        while(true) {
            if(word[x] == maxchar) {
                word[x] == minchar;
                --x;
            }
            else {
                // printf("%d %d %d %c\n", x, word[x], values[word[x]], abc[values[word[x]]]);
                word[x] = abc[values[word[x]] + 1];
                break;
            }
        }
        
        // is interesting?
        int is_interesting = 1;
        int all_same = 1;
        for(int split = 1; split < k; ++split) {
            for(int ii = 0; ii < k; ++ii) {
                char snd = word[(ii + split) % k];
                if(word[ii] > snd) {
                    is_interesting = 0;
                    break;
                }
                if(word[ii] < snd) {
                    all_same = 0;
                    break;
                }
            }
            if(all_same)
                is_interesting  = 0;
            if(!is_interesting)
                break;
        } 
            
        if(is_interesting) {
            //printf("--> %s\n", word);
            temp++;
        }
        else {
            //printf("X %s\n", word);
        }
    }
    
    
    FILE* out = fopen("nthword.out", "wt");
    fprintf(out, "%s", word);
    fclose(out);
    
	
	return 0;
}