from math import sqrt
def divisor(N):
    ret = []
    for i in range(1,int(sqrt(N))+1):
        if N % i == 0:
            ret.append(i)
            if N // i != i:
                ret.append(N//i)
    ret.sort()
    return ret

N = int(input())
D = divisor(N)
for d in D:
    if d <= 2:
        continue
    print(d)
    break