def make_divisors(n):
    divisors = []
    i = 1
    while i * 2 <= n:
        if n % i == 0:
            divisors.append(i)
        i += 1
    return divisors

N = int(input())
D = make_divisors(N)
ans = N - 1
for a in D:
    n = N // a
    D2 = make_divisors(n-1)
    if len(D2) == 1:
        break
    D2.remove(1)
    flag = 0
    for p in D2:
        if a >= p:
            continue
        tmp = 1
        p2 = p
        while tmp < n:
            tmp += p2
            if n - 1 == p * tmp:
                ans = min(p,ans)
                flag = 1
                break
            p2 *= p
        if flag == 1:
            break

print(ans)