An apprentice alchemist owns a warding scroll that begins as a single inked rune: the letter a. Each night the alchemist performs the same ritual: the entire current scroll is copied, and the copy is appended to the end of the original scroll — but every rune on the freshly appended copy is advanced one letter forward in the alphabet (a becomes b, b becomes c, ..., and z wraps back around to a). The scroll therefore doubles in length every night. The ritual repeats, night after night, until the scroll holds at least k runes; the alchemist then stops and reads off the rune sitting in the k-th position, counting the very first rune as position 1.

Given k, determine which rune occupies position k once the ritual stops.

Input format

A single line containing one integer, k.

Output format

A single line containing one lowercase letter: the rune at position k.

Constraints

• 1 <= k <= 100000

5

b

8

d