DSA02030 - LIỆT KÊ XÂU KÝ TỰ

//Made By Phuong Nam PROPTIT <3//
#pragma GCC Optimize("O3")
#include<bits/stdc++.h>
#include<string>
#include<vector>
#define alphaa "abcdefghijklmnopqrstuvwxyz"
#define ALPHAA "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
#define f(i,a,b) for(int i=a;i<=b;i++)
#define f1(i,n) for(int i=1;i<=n;i++)
#define f0(i,n) for(int i=0;i<n;i++)
#define ff(i,b,a) for(int i=b;i>=a;i--)
#define el cout<<'\n'
#define fi first
#define se second
#define pb push_back
#define pk pop_back
#define vi vector<int>
#define vl vector<ll>
#define pii pair<int,int>
#define pll pair<ll,ll>
#define all(s) s.begin(),s.end()
using namespace std;
typedef long long ll;
const int N=1e6+3;
const int MOD=1e9+7;
template<class X,class Y>
    void minimize(X &x,const Y &y) {
        if (x>y) x=y;
    }
template<class X,class Y>
    void maximize(X &x,const Y &y) {
        if (x<y) x=y;
    }
template<class T>
    T Abs(const T &x) {
        return (x<0?-x:x);
    }
char c;
int d,a[20],kt=1;
string s="";
void xuly()
{
    cin>>c>>d;
    for(char i='A';i<=c;i++) s+=i;
    int n=s.size();
    s=' '+s;
    f1(i,d) a[i]=1;
    while(kt)
    {
       bool check=1;
       f1(i,d)
       {
           f(j,i+1,d)
           {
               if(a[j]<a[i]) {check=0;break;}
           }
       }
       if(check)
       {
           f1(i,d) cout<<s[a[i]];
           el;
       }
       int i=d;
       while(i&&a[i]==n) i--;
       if(i)
       {
          a[i]++;
          f(j,i+1,d) a[j]=1;
       }
       else kt=0;
    }
}
int main()
{
  ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
  int t=1;
  //cin>>t;
  while(t--) xuly();
  return 0;
}
//-----YEU CODE HON CRUSH-----//