def primeFactor(N):
    i, n, ret, d, sq = 2, N, {}, 2, 99
    while i <= sq:
        k = 0
        while n % i == 0: n, k, ret[i] = n//i, k+1, k+1
        if k > 0 or i == 97: sq = int(n**(1/2)+0.5)
        if i < 4: i = i * 2 - 1
        else: i, d = i+d, d^6
    if n > 1: ret[n] = 1
    return ret
def divisors(N):
    pf = primeFactor(N)
    ret = [1]
    for p in pf:
        ret_prev = ret
        ret = []
        for i in range(pf[p]+1):
            for r in ret_prev:
                ret.append(r * (p ** i))
    return sorted(ret)

N = int(input())
for p in range(2, 10 ** 6 + 10):
    s = 0
    a = 1
    f = 0
    while s < N:
        s += a
        a *= p
        if N % s == 0 and N // s < p:
            f = 1
            break
    if f:
        print(p)
        break
else:
    for d in divisors(N):
        a = N // d
        if a < d - 1:
            print(d - 1)
            break