def is_prime(n):
    
    ans = []

    m = int(n ** 0.5)

    if m == n / m:
        ans.append(m)

    for i in range(1, m):
        if n % i == 0:
            ans.append(i)
            ans.append(n // i)
    ans.sort()

    return ans

n = int(input())

for i in is_prime(n):
    if i == 1 or i == 2:
        continue
    else:
        print(i)
        break