Problem:
Score : 300 points

Problem Statement

1000000000000001 dogs suddenly appeared under the roof of Roger's house, all of which he decided to keep. The dogs had been numbered 1 through 1000000000000001, but he gave them new names, as follows:

the dogs numbered 1,2,\cdots,26 were respectively given the names a, b, ..., z;

the dogs numbered 27,28,29,\cdots,701,702 were respectively given the names aa, ab, ac, ..., zy, zz;

the dogs numbered 703,704,705,\cdots,18277,18278 were respectively given the names aaa, aab, aac, ..., zzy, zzz;

the dogs numbered 18279,18280,18281,\cdots,475253,475254 were respectively given the names aaaa, aaab, aaac, ..., zzzy, zzzz;

the dogs numbered 475255,475256,\cdots were respectively given the names aaaaa, aaaab, ...;

and so on.

To sum it up, the dogs numbered 1, 2, \cdots were respectively given the following names:

a, b, ..., z, aa, ab, ..., az, ba, bb, ..., bz, ..., za, zb, ..., zz, aaa, aab, ..., aaz, aba, abb, ..., abz, ..., zzz, aaaa, ...

Now, Roger asks you:

"What is the name for the dog numbered N?"

Constraints

N is an integer.

1 \leq N \leq 1000000000000001

Input

Input is given from Standard Input in the following format:

N

Output

Print the answer to Roger's question as a string consisting of lowercase English letters.

Sample Input 1

2

Sample Output 1

b

Sample Input 2

27

Sample Output 2

aa

Sample Input 3

123456789

Sample Output 3

jjddja

Solution in C++ (GCC 9.2.1) (judge verdict: Wrong Answer)

//include,namespace
 #include<bits/stdc++.h>
 #include<iostream> 
 #include <queue>
 #include <vector>
 #include <string>
 using namespace std;
//REPmacro
 #define all(x) (x).begin(),(x).end()             //ソート
 #define FOR(i,x,n)for(int i=(x);i<(n);i++)
 #define FOR_R(i,x,n) for(int i=(n-1);i>=(x);i--)
 #define REP(i, n) FOR(i, 0, n)
 #define REP_R(i, n) FOR_R(i, 0, n)
//long long(define)
 using ll = long long;
 typedef long long ll;
 typedef long long int64;
 typedef long long lint;
 typedef long long lli;

////////////////いろいろあるよ//////////////////////////////////
int main(){
	ll n;
  	cin >> n;
  	stack<int> s;
  	char alpha[26] = {'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'};
  
  	while(true){
      	if(n/26==0)break;
    	s.push(n%26);
      	n /= 26;
    }
  
  	if(n!=0)cout << alpha[n-1];

  	while(!s.empty()){
    	int a;
      	a = s.top();
      	s.pop();
      	if(a==0)cout << 'a';
      	else cout << alpha[a-1];
      	
    }
  cout << endl;
  
}