def isqrt(n):
    return int(floor(sqrt(n)))

def usqrt (n):
    ur = isqrt(n)
    if ur ** 2 < n:
        ur = ur + 1
    return(ur)

def FermatAttack (n, rounds):
    st = usqrt(n)
    for x in range(st, st + rounds + 1):
        sq = x ** 2 - n
        y = isqrt(sq)
        if y ** 2 == sq:
            print("Factor found in round %d\n", x - st + 1)
            return(x + y)
    print("No factors found in %d \n", rounds)

FermatAttack(next_prime(1178900875984375493875975943857489375948375498375948375943875)*next_prime(1178900875984375493875975943857489375948375498375948375943876),10000)