#include<iostream>
using namespace std;

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