#include <iostream>
using namespace std;

int main(){
    int height;
    cin>>height;
    if(height<1|| height>26){
        cout<"Invalid input";
        return 0;
        
    }
    for(int i=1; i<= height; 1++)
    {
        for(int j = 0; j<i; j++)
        cout << char('A'+ j);
        cout << endl;
    }
    return 0;
    
}