import java.math.BigInteger;

import java.util.Scanner;

public class Main {

    static BigInteger MAX(BigInteger a,BigInteger b)

    {

        if(a.compareTo(b)>=) return a;

        return b;

    }

    public static void main(String args[]){

        Scanner cin = new Scanner(System.in);

        int n,k;

        String x;

        BigInteger  dp[][] = new BigInteger [][];

        while(cin.hasNext())

        {

            n = cin.nextInt();

            k = cin.nextInt(); k++;

            x = cin.next();

            for(int i=;i<x.length();i++)

            {

                for(int j=;j<=k;j++) dp[i][j] = BigInteger.ZERO;

            }

            String y = "";

            for(int i=;i<x.length();i++)

            {

                y=y+x.charAt(i);

                dp[i][] = new BigInteger(y);

            }

            for(int j=;j<=k;j++)

            {

                for(int i=j-;i<x.length();i++)

                {

                    for(int p=j-;p<i;p++)

                    {

                        y =  "";

                        for(int g=p+;g<=i;g++) y=y+x.charAt(g);

                        dp[i][j]=MAX(dp[i][j],dp[p][j-].multiply(new BigInteger(y)));

                    }

                }

            }

            System.out.println(dp[x.length()-][k]);

        }

    }

}