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:
def digit_sum(x: int, b: int) -> int:
    total = 0
    while x > 0:
        total = total + (x % b)
        x = x // b
    return total

def digital_root(x: int, b: int) -> int:
    seen = set()
    while x not in seen:
        seen.add(x)
        x = digit_sum(x, b)
    return x


digit = int(input())
print(digital_root(digit,10))