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