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