n = int(input())
if n <= 2:
    print(n + 1)
    exit()

def ok(p):
    m = n
    x = m % p
    m //= p
    while m > 0:
        if m % p != x:
            return False
        m //= p
    return True

ans = n - 1
for p in range(2, int(n ** 0.5 + 1)):
    if ok(p):
        print(p)
        exit()

    if n % p == 0:
        x = n // p - 1
        if x > p:
            ans = min(ans, x)
print(ans)