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