def make_divisors(n):
    lower_divisors , upper_divisors = [], []
    i = 1
    while i*i <= n:
        if n % i == 0:
            lower_divisors.append(i)
            if i != n // i:
                upper_divisors.append(n//i)
        i += 1
    return lower_divisors + upper_divisors[::-1]
N = int(input())
L = make_divisors(N)
for i in reversed(range(len(L))):
    if (N*(N-1)//2)%L[i]==0:
        print(L[i])
        exit()