using System;
using System.Linq;

public class Test
{
	public static void Main()
	{
		string record1 = "1,3,5,7,9,10";
		string record2 = "4,5,10";
		string[] records = new[] { record1, record2 };
		string record = records.FirstOrDefault(r => r.Split(',').Any(s => s == "1"));
		Console.WriteLine(record);
	}
}