#include <iostream>

void print_filled_rectangle(int h, int w, char c) {
    for (int i = 0; i < h; i++) {
        for (int j = 0; j < w; j++) {
            std::cout << c;
        }
        std::cout << std::endl;
    }
}

void print_unfilled_rectangle(int h, int w, char c) {
    for (int i = 0; i < w; i++) {
        std::cout << c;
    }
    std::cout << std::endl;
    for (int i = 0; i < h - 2; i++) {
        std::cout << c;
        for (int j = 0; j < w - 2; j++) {
            std::cout << " ";
        }
        std::cout << c << std::endl;
    }
    for (int i = 0; i < w; i++) {
        std::cout << c;
    }
    std::cout << std::endl;
}

int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);

    int h, w;
    char c;
    bool filled;

    while (std::cin >> h >> w >> c >> filled) {
        if (filled) {
            print_filled_rectangle(h, w, c);
        } else {
            print_unfilled_rectangle(h, w, c);
        }
    }

    return 0;
}