N = int(input())
if N == 1:
    print(2)
    exit()

P = [[1] * 45 for i in range(1000)]
inf = 10 ** 18
for i in range(1000):
    for j in range(44):
        P[i][j + 1] = min(inf, P[i][j] * i)

def f(p, d):
    if p >= 10 ** 9:
        return inf
    if p >= 10 ** 6 and d >= 3:
        return inf
    if p >= 10 ** 4 and d >= 4:
        return inf
    return (p ** d - 1) // (p - 1)

ans = N + 1
for d in range(2, 45):
    for v in range(1, 10**18):
        if v * f(v + 1, d) > N:
            break
        yes = v + 1
        no = N + 1
        if no <= yes:
            break
        while no - yes != 1:
            mid = (yes + no)//2
            if v * f(mid, d) <= N:
                yes = mid
            else:
                no  = mid
        if v * f(yes, d) == N:
            ans = min(ans, yes)

print(ans)