using System;

using System.Xml;

using System.Xml.Serialization;

using System.IO;

using System.Linq;

using System.Collections;

using System.Collections.Generic;

using System.Xml.Linq;

using System.Data;

using System.Collections.Specialized;

using System.Text.RegularExpressions;

using System.Globalization;

using System.Diagnostics;

public class Program

{

    public static void Main()

    {

        string input = @"<battle>

  <alliance id=""0"">

    <army>

      <faction>rom_athens</faction>

      <unit>

        <unit_type type=""unit_A"" />

        <general>

          <commander_record_key>commanderName</commander_record_key>

        </general>

        <unit_capabilities>

          <special_ability>abilityName</special_ability>

        </unit_capabilities>

      </unit>

      <unit>

        <unit_type type=""unit_A"" />

        <unit_capabilities>

          <special_ability>abilityName</special_ability>

        </unit_capabilities>

      </unit>

      <unit>

        <unit_type type=""unit_A"" />

        <unit_capabilities>

          <special_ability>abilityName</special_ability>

          <special_ability>abilityName</special_ability>

        </unit_capabilities>

      </unit>

    </army>

    <army>

      <faction>rom_arverni</faction>

      <unit>

        <unit_type type=""unit_A"" />

        <general>

          <commander_record_key>commanderName</commander_record_key>

        </general>

        <unit_capabilities>

          <special_ability>abilityName</special_ability>

          <special_ability>abilityName</special_ability>

        </unit_capabilities>

      </unit>

      <unit>

        <unit_type type=""unit_B"" />

        <unit_capabilities>

          <special_ability>abilityName</special_ability>

        </unit_capabilities>

      </unit>

      <unit>

        <unit_type type=""unit_B"" />

        <unit_capabilities>

          <special_ability>abilityName</special_ability>

          <special_ability>abilityName</special_ability>

        </unit_capabilities>

      </unit>

    </army>

    <army>

      <faction>rom_rome</faction>

      <unit>

        <unit_type type=""unit_C"" />

        <general>

          <commander_record_key>commanderName</commander_record_key>

        </general>

        <unit_capabilities>

          <special_ability>abilityName</special_ability>

          <special_ability>abilityName</special_ability>

        </unit_capabilities>

      </unit>

      <unit>

        <unit_type type=""unit_C"" />

        <unit_capabilities>

          <special_ability>abilityName</special_ability>

        </unit_capabilities>

      </unit>

      <unit>

        <unit_type type=""unit_C"" />

        <unit_capabilities>

          <special_ability>abilityName</special_ability>

        </unit_capabilities>

      </unit>

    </army>

    <victory_condition>

      <kill_or_rout_enemy />

    </victory_condition>

  </alliance>

  <alliance id=""1"">

    <army>

      <faction>rom_rome</faction>

      <unit>

        <unit_type type=""unit_F"" />

        <general>

          <commander_record_key>commanderName</commander_record_key>

        </general>

        <unit_capabilities>

          <special_ability>abilityName</special_ability>

        </unit_capabilities>

      </unit>

      <unit>

        <unit_type type=""unit_F"" />

        <unit_capabilities>

          <special_ability>abilityName</special_ability>

        </unit_capabilities>

      </unit>

      <unit>

        <unit_type type=""unit_F"" />

        <unit_capabilities>

          <special_ability>abilityName</special_ability>

        </unit_capabilities>

      </unit>

    </army>

    <army>

      <faction>rom_athens</faction>

      <unit>

        <unit_type type=""unit_F"" />

        <general>

          <commander_record_key>commanderName</commander_record_key>

        </general>

        <unit_capabilities>

          <special_ability>abilityName</special_ability>

        </unit_capabilities>

      </unit>

      <unit>

        <unit_type type=""unit_F"" />

        <unit_capabilities>

          <special_ability>abilityName</special_ability>

        </unit_capabilities>

      </unit>

      <unit>

        <unit_type type=""unit_F"" />

        <unit_capabilities>

          <special_ability>abilityName</special_ability>

        </unit_capabilities>

      </unit>

    </army>

    <army>

      <faction>rom_arverni</faction>

      <unit>

        <unit_type type=""unit_F"" />

        <general>

          <commander_record_key>commanderName</commander_record_key>

        </general>

        <unit_capabilities>

          <special_ability>abilityName</special_ability>

        </unit_capabilities>

      </unit>

      <unit>

        <unit_type type=""unit_F"" />

        <unit_capabilities>

          <special_ability>abilityName</special_ability>

        </unit_capabilities>

      </unit>

      <unit>

        <unit_type type=""unit_F"" />

        <unit_capabilities>

          <special_ability>abilityName</special_ability>

        </unit_capabilities>

      </unit>

    </army>

    <victory_condition>

      <kill_or_rout_enemy />

    </victory_condition>

  </alliance>

</battle>";

        XDocument doc = XDocument.Parse(input);

​

        var results = doc.Descendants("alliance")

                         .Select(g=> 

                                 new 

                                 {

                                     ID = g.Attribute("id").Value, 

                                     ArmyCount =   g.Elements("army").Count() 

                                 });

        foreach(var result in results)

        {

            Console.WriteLine(result);

        }

​

    }

}