package main

import (
	"fmt"
)

func Sqrt(x float64) float64 {
	z := float64(1)
  for i:=0; i<10; i++ {
    z -= (z*z-x)/(2*z)
  }
	return z
}

func main() {
	fmt.Println(Sqrt(2))
	fmt.Println(Sqrt(4))
	fmt.Println(Sqrt(122))
}