System Diagnostics Problem

so i want to start cmd but this one error keeps popping up

Error > error CS0103: The name `Process’ does not exist in the current context

using System.Diagnostics;
using UnityEngine;

public class CMDManager : MonoBehaviour
{
    private void Start()
    {
        Process.Start("cmd.exe");
    }
}

well when i right click the solution explorer add reference doesn’t show and this problem has been bugging me for 2 hours i think this server cmd is not worth it in any case i will reinstall vs for unity and see if that solve my problem thanks!