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 Java (OpenJDK 1.8.0) (judge verdict: Runtime Error)

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.Stack;

public class Main {
    private static final Reader reader = new Reader();

    public static void main(String[] args) throws Exception{
        long n = reader.readLong();
        Stack<Character> stack = new Stack<>();
        while(n>0){
            n--;
            int dig = (int)(n%26);
            stack.add((char)('a'+dig));
            n/=26;
        }
        StringBuffer sb = new StringBuffer();
        while(!stack.isEmpty())
            sb.append(stack.pop());
        System.out.println(sb.toString());
    }


    private static class Reader{
        private final BufferedReader br;
        public Reader(){
            br = new BufferedReader(new InputStreamReader(System.in));
        }
        public int readInt() throws Exception{
            return Integer.parseInt(br.readLine());
        }
        public int readLong() throws Exception {
            return Integer.parseInt(br.readLine());
        }
        public double readDouble() throws Exception {
            return Double.parseDouble(br.readLine());
        }
        public String readLine() throws Exception{
            return br.readLine();
        }
        public int[] readIntArray() throws Exception{
            String[] tokens = br.readLine().split(" ");
            int[] nums = new int[tokens.length];
            for(int i=0;i<tokens.length;i++){
                nums[i] = Integer.parseInt(tokens[i]);
            }
            return nums;
        }
        public long[] readLongArray() throws Exception{
            String[] tokens = br.readLine().split(" ");
            long[] nums = new long[tokens.length];
            for(int i=0;i<tokens.length;i++){
                nums[i] = Long.parseLong(tokens[i]);
            }
            return nums;
        }
        public double[] readDoubleArray() throws Exception {
            String[] tokens = br.readLine().split(" ");
            double[] nums = new double[tokens.length];
            for(int i=0;i<tokens.length;i++){
                nums[i] = Double.parseDouble(tokens[i]);
            }
            return nums;
        }
        public String[] readWords() throws Exception {
            return br.readLine().split(" ");
        }
    }
}