Problem: Many people are aware of DMCA – Digital Millennium Copyright Act. But another recently proposed DMCA – Digital Millennium Calculation Act – is much less known.

In this problem you need to find a root of a number according to this new DMCA law.

Input

The input contains a single integer a (1 ≤ a ≤ 1000000).

Output

Output the result – an integer number.

Examples

Input


1


Output


1


Input


81


Output


9

Solution (in PYTHON3):

Solution:
x = int(input())

def digit_sum(n):
    if n < 10:
        return n
    return n % 10 + digit_sum(n//10)

def digit_root(n):
    if n < 10:
        return n
    return digit_root(digit_sum(n))
print(digit_root(x))