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