import java.io.*;
import java.util.*;
import java.math.*;
import static java.lang.Math.*;

public class Main{
    public static void main(String[] args) throws IOException{
        in = new StreamTokenizer(new BufferedReader(new FileReader (new File("input.txt"))));
        inBuf = new BufferedReader (new FileReader (new File ("input.txt")));
        out = new PrintWriter(new File ("output.txt"));

        int n=Integer.valueOf (nextSBuf());
        String num=nextSBuf();
        int k=Integer.valueOf (nextSBuf());

        int mid=toTenth(n, num);

        out.println (toKth(mid, k));

        out.close();
    }

    public static String toKth(int tenth, int to){
        String result="";
        for (;;){
            result=convertToChar (tenth%to, to)+result;
            tenth/=to;
            if (tenth==0) break;
        }
        return result;
    }

    public static char convertToChar(int num, int t){
        String hlp="0123456789";
        for (char i='A'; i<='Z'; i++) hlp+=i;
        return hlp.charAt(num);
    }

    public static int toTenth(int sys, String number){
        int res=0, power=number.length()-1;

        for (int i=0; i<number.length(); i++, power--){
            res=res+convertToNumber(number.charAt(i))*(int)(pow (sys, power));
        }

        return res;
    }

    public static int convertToNumber(char c){
        String hlp="0123456789";
        for (char i='A'; i<='Z'; i++) hlp+=i;
        for (int i=0; i<hlp.length(); i++)
            if (hlp.charAt(i)==c) return i;

        //never
        return 0;
    }

    static StreamTokenizer in; static PrintWriter out; static BufferedReader inBuf;
    public static String nextSBuf() throws IOException{
        return inBuf.readLine();
    }
    public static long nextL() throws IOException{
        in.nextToken(); return (long)in.nval;
    }
    public static double nextD() throws IOException{
        in.nextToken(); return in.nval;
    }
    public static String nextS() throws IOException{
        in.nextToken(); return in.sval;
    }
    public static int nextI() throws IOException{
        in.nextToken(); return (int)in.nval;
    }