from math import *

def Dfermat(n):
    q=floor(sqrt(n))
    if q*q==n :
        L=[q,q]
    else:
        a=q+1
        d=2*a+1
        b2=a**2-n
        while floor(sqrt(b2))**2 != b2:
          b2 = d +b2
          a = a + 1
          d = d + 2
        b = sqrt(b2)
        L= [a+b,a-b]
    return L