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