#include <iostream>

using namespace std;

int main()
{
    string vystup_x, vystup_1, vystup_2;
    vystup_1="_";
    int a = 0;
    cout << "Zdejte pocet schodu A:" << endl;
    int pocet;
    cin >> pocet;
    if ((!cin.fail())&& (pocet>=0))
        {for (int a; a<=pocet; a++)
        {if (a==1){
            cout << vystup_1 << endl;}
        else cout << vystup_x = "X" + vystup_1 << endl;
        }
            cout << "X" << endl;}

    else cout << "Spatny vstup." << endl;

    return 0;
}