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