#include<bits/stdc++.h>
using namespace std;
int main(){
    int a, b, n;
    char c;
    cin>>a>>b>>c>>n;
    for(int i = 1; i <= a; i++){
        for(int j = 1; j <= b; j++){
            if(n == 0){
                if(j == 1 || j == a || i == 1 || i == b){
                    cout<<c;
                }
                else{
                    cout<<' ';
                }
            }
            else{
                cout<<c;
            }
        }
        cout<<endl;
    }
    return 0;
}