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 Kotlin (1.3.71) (judge verdict: Wrong Answer)

fun main(){
    val n = readLine()!!.split(" ")[0].toLong()
    val hikukazu = mutableListOf<Long>()
    var x = 1L
    var useNum = n
    var keta = 0
    for (i in 0 until 100000){
        x *= 26
        if (x > 1000000000000001) break
        hikukazu.add(x)
    }
    for (i in 0 until hikukazu.size){
        if (useNum <= hikukazu[i]){
            keta = i + 1
            break
        } else {
            useNum -= hikukazu[i]
        }
    }

    var kuriagariFlag = 0
    var ansList = mutableListOf<Char>()
    for (i in 0 until keta-1){
        if (i == 0){
            var xx = useNum % 26 + 96
            if (xx == 96L){
                xx += 26
                kuriagariFlag = 1
            }
            ansList.add(xx.toChar())
        } else {
            var xx = useNum % 26 + 97
            if (xx == 97L){
                xx += 25
                kuriagariFlag = 1
            }
            ansList.add(xx.toChar())
        }
        useNum /= 26
    }
    if (keta != 1){
        if (kuriagariFlag == 0){
            useNum += 97
            ansList.add(useNum.toChar())
        } else {
            useNum += 96
            ansList.add(useNum.toChar())
        }
    } else {
        ansList.add((n+96).toChar())
    }

    var ans = ""
    for (i in 0 until keta){
        ans += ansList[keta - 1 - i]
    }
    println(ans)
}