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