How to find integer nth roots?

Question

I want to find the greatest integer less than or equal to the kth root of n. I tried

int(n**(1/k))

But for n=125, k=3 this gives the wrong

Answer 1

def nth_root(n, k):
    x = n**(1./k)
    y = int(x)
    return y + 1 if y != x else y