N = int(input())

#約数の後半列挙
def make_divisors(n):
    lower_divisors , upper_divisors = [], []
    i = 1
    while i*i < n:
        if n % i == 0:
            lower_divisors.append(i)
            if i != n // i:
                upper_divisors.append(n//i)
        i += 1
    return upper_divisors[::-1]

#めぐる式二部探索
#参考サイト：https://aotamasaki.hatenablog.com/entry/meguru_bisect

def is_ok(arg,tar,n):
    # 整数を買えればTrueを返す
    return (arg**n-1)//(arg-1) <= tar

def meguru_bisect(ng, ok, tar, n):
    while (abs(ok - ng) > 1):
        mid = (ok + ng) // 2
        if is_ok(mid,tar,n):
            ok = mid
        else:
            ng = mid
    return ok

L=make_divisors(N)
ans = N-1

for l in L:
    for i in range(2,40):
        temp = meguru_bisect(N + 1, 1 ,l ,i)
        if temp>1 and (temp**i)//(temp-1)==l:
            ans = min(temp,ans)

print(ans)