N = int(input())

def factor(x):
    f=[]
    while x % 2 == 0:
        if 2 in f:
            f.remove(2)
            f.append(4)
        else:
            f.append(2)
        x = x / 2
    n=3
    while x >= n * n:
        while x % n == 0:
            f.append(n)
            x = x / n
        n = n + 2
    if x == 1:
        return f
    f.append(int(x))
    return  f

for n in sorted(factor(N)):
    if n != 2:
        print(n)
        exit()