// editor1
#include<iostrem>
using namespace std;
int main(){
    int height;
    cin>>height;
    if(height<1||height>26){
        cout<<"invalid input";
    }else{
        for(inti=1;i<=height;i++){
        for(int j=0;j<i;j++){
            cout<<char('A'+j);
        }
        cout<<endl;
    }
}
return 0;
}