#include <iostream>
using namespace std;
void printalpha(int height){
    if (height<1 || height >26){
        cout << "Invalid input";
        return;
}
for (int i=1; i <= height; i++){
    char letter = 'A';
    for (int j=1; j<=i;j++){
        cout <<letter<<" ";
        letter++;
        
    }
    cout>>endl;
    }}
    
int main (){
    int height;
    cin >> height;
    printalpha(height);
    return 0;
    
}