using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        var myDictionary = new Dictionary<string, int>();

        myDictionary.Add("something", 5);

        myDictionary.Add("something else", 15);

​

        foreach (var key in myDictionary.Keys) 

        {

            myDictionary[key] -= 1;

        }

​

        myDictionary.Dump();

    }

}