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 <iostream>
#include<cmath>
#include<string>
#include<algorithm>
#include<ctime>
#include<functional>
#include<vector>
#include<stack>
#include<queue>
#include<deque>
#include<list>
#include<map>
#include<set>
#include<tuple>
#include<cassert>
#include<bitset>
#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<cctype>
#include<iomanip>
#include<climits>
#include<typeinfo>
#include<utility>
#define rep(i,n) for(int i=0;i<n;i++)
#define Rep(i,n) for(ll i=0;i<n;i++)
#define For(i,m,n) for(int i=m;i<n;i++)
#define FOR(i,m,n) for(ll i=m;i<n;i++)
double pi = 3.141592653589793238;
using ll = long long;
using namespace std;

ll LGCD(ll x, ll y) { if (x % y == 0) return y;else return LGCD(y, x % y); }
ll LLCM(ll x, ll y) { return x * y / LGCD(x, y); }

int GCD(int x, int y) { if (x % y == 0) return y;else return GCD(y, x % y); }
int LCM(int x, int y) { return x * y / GCD(x, y); }
ll dpcombination[10000][10000];

ll modi = 1000000007;
ll combination(ll n, ll r) {
	if (n == r) { return dpcombination[n][n] = 1; }
	else if (r == 0) { return dpcombination[n][0] = 1; }
	else if (r == 1) { return dpcombination[n][1] = n; }
	else if (dpcombination[n][r]) { return dpcombination[n][r]; }
	else { return dpcombination[n][r] = combination(n - 1, r - 1) % modi + combination(n - 1, r) % modi; }
}

void clockman(int time1) {

	cout << 1.0*(clock() - time1) / CLOCKS_PER_SEC << endl;
	return;
}
//cout << fixed << setprecision(10)

void printVec(std::vector<int> &vec) {
	std::cout << "";
	for (auto it = vec.begin(); it != vec.end(); ++it) {
		std::cout << *it << " ";
	}
	std::cout << std::endl;
}


int main() {

	ll index;
	cin >> index;

	string s = "";
	while (1) {
		if (index <= 26)break;
		//対象を26で割った余り
		int amari = index % 26;
		//対象を26で割った商
		int sho = index / 26;
		if (amari == 0)
		{
			amari = 26;
			sho--;
		}
		s = ((char)((int)'a' + amari - 1)) + s;

		//商を次の対象とする
		index = sho;
		
	}
	s= ((char)((int)'a' + index - 1)) + s;

	cout << s << endl;
	return 0;
}