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

int a, b, f;
char ch;

int main(){
	scanf("%d%d", &a, &b);
	cin >> ch;
	scanf("%d", &f);
	for (int i = 1; i <= a; i++)
		cout << ch;
	printf("\n");
	for (int i = 2; i <= a - 1; i++) {
		for (int j = 1; j <= b; j++)
			if (j == 1 || j == b)
				cout << ch;
			else
				if (f == 0)
					printf(" ");
				else
					cout << ch;
		printf("\n");
	}
	for (int i = 1; i <= a; i++)
		cout << ch;
	printf("\n");
}