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<stdio.h>

#define ll long long

ll power(int a, int b){
	int tmp = a;
	if(b == 0){
		return 1;
	}
	else{
		for(int i = 1; i < b; i++){
			tmp *= a;
		}
		return tmp;
	}
}

int main(){
	char str[500];
	scanf("%s", str);
	ll n = 0;
	int len = 0;
	for(int i = 0; str[i] != '\0'; i++){
		len++;
	}
	for(int i = 0; i < len; i++){
		if(str[i] == '1'){
			n += power(2, (len - 1) - i);
		}
	}
	int ctr = 0;
	while(n != 1){
		if(n == 1){
			break;
		}
		if(n % 2 == 1){
			n += 1;
			ctr++;
		}
		else{
			n /= 2;
			ctr++;
		}
	}
	printf("%d\n", ctr);
	return 0;
}