// editor2
#include<iostream>
using namespace std;
int main(){
    void triangle(int n){
        if(n<1 || n>26){
            cout<<"Invalid input";
            return 0;
        }
        for(inti=1,i<=n,i++){
            for(int j=0;j<i,j++){
            cout<<char('A'+j)
        }
        cout<<endl;
    }
    int main(){
        int height;
        cin>>height;
        triangle(height);
        return 0;
        
        
    }