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:
    print(N - 1)