#include <cstdio>
int main(){
    int  m,n,k;
    char ch;
    scanf("%d %d %c %d", &m,&n,&ch,&k);
    if(k==0){
        for (int i = 1; i <= m; i++){
            for (int j = 1; j <= n; j++){
                if(i ==1 || i == m || j==1 || j==n){
                    printf("%c",ch);
                }
                else{
                    printf(" ");
                }
            }
            printf("\n");
        }
    }
    else{
        for (int i = 1; i <= m; i++){
            for (int j = 1; j <= n; j++){
                printf("%c",ch);
            }
            printf("\n");
        }        
    }
    return 0;
}