#include <bits/stdc++.h>
using namespace std;

int main() 
{
    int a, b, c;
    char n;
    cin >> a >> b >> n >> c;
    for (int i = 1; i <= a; i++)
    {
        for (int j = 1; j <= b; j++)
        {
            if (c == 1 or i == a or i == 1 or j == b or j == 1)
            {
                cout << n;
            }
            else
            {
                cout << " ";
            }
        }
        cout << '\n';
    
    
    }   

    return 0;
}