#include <bits/stdc++.h>

using namespace std;

int main() {
    int a, b, s;
    char c;
    cin >> a >> b >> c >> s;
    for (int i = 1; i <= a; i++) {
        for (int j = 1; j <= b; j++) {
            if (s)printf("%c", c);
            else if (i==1 || i==a || j == 1 || j == b) printf("%c", c);
            else printf("%c",' ');
        }
        printf("\n");
    }
    return 0;
}