16分求助！！！！

#include <iostream>
#include <cstdio>
using namespace std;
int main()
{
	char a[28]={"0ABCDEFGHIJKLMNOPQRSTUVWXYZ"};
	int n;
	cin >> n;
	int ans=0;
	for(int i=1;i<=n;i++)
	{
		for(int j=1;j<=i;j++)
		{
			ans++;
			if(ans<=26)
			{
				cout << a[ans];
			}
			else
			{
				cout << a[ans-26];
			}
		}
		cout << endl;
	}
	return 0;
}