Calculate the positive min difference between 2 values in a array using Dictionary

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace CSharpGitHubPgm
{
    class Program
    {
        static void Main(string[] args)
        {

            int[] arr = {1,9,4,3};
            Dictionary<string, int> storeDiffbetweenNumbers = new Dictionary<string, int>();
            Console.WriteLine("To find the minimum difference between the array");
            for (int i = 0; i < arr.Length; i++)
            {
                for (int j = i+1; j < arr.Length; j++)
                {
                    int diff = arr[i] - arr[j];
                    string key = Convert.ToString(arr[i] +"-"+ arr[j]);
                    storeDiffbetweenNumbers.Add(key, diff);
                }
            }

            var t = storeDiffbetweenNumbers.Where(x => x.Value > 0).Select(x => x).Min(x=>x.Value);
            Console.WriteLine(t);
            Console.ReadLine();
        }
    }
}