Problem:
Score : 600 points

Problem Statement

Given is an integer N.
Find the minimum possible positive integer k such that (1+2+\cdots+k) is a multiple of N.
It can be proved that such a positive integer k always exists.

Constraints

1 \leq N \leq 10^{15}

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N

Output

Print the answer in a line.

Sample Input 1

11

Sample Output 1

10

1+2+\cdots+10=55 holds and 55 is indeed a multple of N=11.
There are no positive integers k \leq 9 that satisfy the condition, so the answer is k = 10.

Sample Input 2

20200920

Sample Output 2

1100144

Solution in Python (3.8.2) (judge verdict: Time Limit Exceeded)

def prime_factorize(n):
    i = 2
    res = {}
    while i * i <= n:
        if n % i != 0:
            i += 1
            continue
        res[i] = 0
        while n % i == 0:
            res[i] += 1
            n //= i
        i += 1
    if n != 1:
        res[n] = 1
    return res
 
 
def solve(n):
    n *= 2
    pf = prime_factorize(n)
    l = len(pf)
    pfk = []
    for i, p in enumerate(pf):
        pfk.append(p ** pf[p])
 
    ans = 10 ** 18
 
    for bit in range(1 << l):
        a = 1
        for d in range(l):
            if bit & (1 << d):
                a *= pfk[d]
        b = n // a
 
        if a == 1:
            k = n - 1
        elif b == 1:
            k = n
        else:
            m = pow(b,-1, a)
            k = b * m - 1
        ans = min(ans, k)
 
    return ans
 
 
n = int(input())
ans = solve(n)
print(ans)