get axis mouse unity

using UnityEngine;
using System.Collections;

// Performs a mouse look.

public class ExampleClass : MonoBehaviour
{
    float horizontalSpeed = 2.0f;
    float verticalSpeed = 2.0f;

    void Update()
    {
        // Get the mouse delta. This is not in the range -1...1
        float h = horizontalSpeed * Input.GetAxis("Mouse X");
        float v = verticalSpeed * Input.GetAxis("Mouse Y");

        transform.Rotate(v, h, 0);
    }
}