#include <iostream> 
  
using namespace std;
  
int main()
  
{
  
	long long m, n,b;
	char a;
	cin >> m >> n >> a >> b;
	for (int i = 1;i <= m;i++)
	{
		if (b != 0)
		{
			for (int k = 0;k <= n;k++)
			{
				cout << a;
             }
		}
		else
		{ 
			if (i == 1 || i == m)
			{
				for (int j = 1;j <= n;j++)
				{

					cout << a;
				}
			}
			else
			{
				for (int j = 1;j <= n;j++)
				{
					if (j == 1 || j == n)
						cout << a;
					else
						cout << " ";
				}
			}

		}
		cout << endl;
	}
	return 0;
}