Change Bits Integer

using System;
using System.Diagnostics;

class ChangeBitsInteger
{
    static void Main()

    {
    //Must change places between 3rd, 4th, 5th and 24th,25th,26th bit in integer number
        var timer = System.Diagnostics.Stopwatch.StartNew();

        Console.Write("Enter a number and see the result of\n changing 3,4,5bit with 24,25,26bit: ");
        int num = int.Parse(Console.ReadLine());
        //Bits 3-24, 4-25, 5-26
        //int num Example = 1234567890; //1001'001'100101100000001011'010'010
        int mask3 = 7 << 3; //7 in Binary is 111, 3 positions left to check 3,4,5bit
        int mask3bits = mask3 & num;
        //Bits 3-0; 4-1; 5-0
        int result3 = mask3bits >> 3; //010

        int mask24 = 7 << 24; //Check 24,25,26 bit
        int mask24bits = mask24 & num;
        //Bits 24-1, 25-0, 26-0
        int result24 = mask24bits >> 24; //001
        //Move 24,25,26 bits to 3,4,5 position
        int replacebits3to24 = result3 << 24;                  //00'010'000000000000
        //Move 3,4,5 bits to 24,25,26 position
        int replacebits24to3 = result24 << 3;                  //00000000000'001'000
        int resultAll = replacebits24to3 | replacebits3to24;   //00'010'0000'001'000
        int oppositemask3 = ~mask3;                //Opposite mask 11111111111000111
        int oppositemask24 = ~mask24;              //Opposite mask 11100011111111111
        int oppositemaskAll = oppositemask24 & oppositemask3; //General opposite mask 111'000'11111111111111'000'111
        int nummask = oppositemaskAll & num;  //Take values from num to General mask  101'000'01000111010001'000'101
        int finalnumber = nummask | resultAll; //3,4,5bit <=> 24,25,26 bit
        Console.WriteLine("Number \"{0}\", gets: \"{1}\"", num, finalnumber);

        var elapsed = timer.ElapsedMilliseconds;
    }
}