#!/usr/bin/python
def conv(num):
    import string
    digits = string.uppercase
    n = len(digits)
    num, rem = divmod(num, n)
    res = digits[rem]
    while num:
        num, rem = divmod(num-1, n)
        res = digits[rem] + res
    return res

n = int(raw_input())
res = conv(n)
print res