C++ :

#include <iostream>
#include <algorithm>
#include <string>
#include <sstream>
using namespace std;

long long f[47][7];

int main()
{
	long long n, m;
	long long i, j, k, cache;
	string s;
	istringstream ss;
	
	cin >> n >> m >> s;
	
	f[1][0] = s[0] - '0';
	for (i = 2; i <= n; i++)
	{
		ss.str(s.substr(0, i));
		ss >> f[i][0];
		ss.clear();
		for (j = 1; j < i; j++)
		{
			ss.str(s.substr(j, i - j));
			ss >> cache;
			ss.clear();
			for (k = 1; k < i && k <= m; k++) f[i][k] = max(f[i][k], f[j][k - 1] * cache);
		}
	}
	
	cout << f[n][m] << endl;
	
	return 0;
}

Pascal :

var  n,m,i,j,k,p:longint;
d:array[1..50,1..10] of int64;
s:string;
function make(p,q:longint):longint;
var x:longint;

 begin
     val(copy(s,p,q),x);
     make:=x;
 end;
begin
      readln(n,m);
      readln(s);
      fillchar(d,sizeof(d),0);
      for i:=1 to n do
       d[i,1]:=make(1,i);
      for k:=2 to m+1 do
       for i:=k to n do
        for j:=i downto k do
         begin
             p:=make(j,i-j+1);
             if d[i,k]<d[j-1,k-1]*p then d[i,k]:=d[j-1,k-1]*p;
         end;
      writeln(d[n,m+1]);
end.