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dfs

#include <iostream>
#include <algorithm>
#include <cmath>
#include <cstring>
using namespace std;

int n, k;
int maxv;
string s;
void dfs(int u, int start, int sum) {
    if(u > k) {
        maxv = max(maxv,sum);
        //cout << sum << endl;
        return ;
    }
    
    int cnt = 0;
    for (int i = start; i < n; i++) {
        cnt = cnt * 10 + (s[i] - '0');
        dfs(u + 1, i + 1, sum * cnt);
    }
}
int main() {
    cin >> n >> k;
    cin >> s;
    dfs(0,0,1);
    cout << maxv << endl;
    return 0;
}