CAU3 HSGHN L9 2015-2016

#define task "CAU3"

#include <iostream>
#include <cstdio>
#include <algorithm>

using namespace std;

constexpr int N = 1e2 + 5;
int k;
string x, s[N];

void Read()
{
    cin >> k >> x;
}

void Solve()
{
    for (int i = 0; i < (int)x.size(); ++i)
    {
        rotate(x.begin(), x.begin() + 1, x.end());
        s[i] = x;
    }

    sort(s, s + x.size());
    int m = unique(s, s + x.size()) - s;

    if (k > m)
        cout << -1;
    else
        cout << s[k - 1];
}

int32_t main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    if (fopen(task ".INP", "r"))
    {
        freopen(task ".INP", "r", stdin);
        freopen(task ".OUT", "w", stdout);
    }

    Read();
    Solve();
}