using System;using System.Collections.Generic;using System.Linq;using System.Threading;using System.Threading.Tasks;using System.Windows.Forms;namespace WindowsFormsApplication3
{static class Program
    {/// /// The main entry point for the application.///         [STAThread]static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);const string appName = "WindowsFormsApplication3";bool createdNew;
            Mutex mut = new Mutex(true, appName, out createdNew);if (!createdNew)
            {
                MessageBox.Show($"WindowsFormsApplication3 is already running!", "Multiple Instances");return;
            }
            Application.Run(new Form1());
        }
    }
}
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