using System;
using System.Linq;
using System.Text.RegularExpressions;

public class Test
{
	public static void Main()
	{
		string pattern = @"\bError importing username: (\d+), primary email: ([^\s@]+@[^\s@,]+)";
		string input = @"string error_message= ""{\""2705\"":\""Error importing username: 3167763, primary email: pkumar194@google.com, error: User already exists but Email does not match: pkumar194@googlee.com vs pkumar193@google.co.in\"",\""10001\"":\""Error importing username: 3195330, primary email: alejandra.mejia@google.com, error: User already exists but Email does not match: alejandra.mejia@google.com vs alejandra.mejia@googlee.com\""}"";";
		
		var collection = Regex.Matches(input, pattern)
		.Cast<Match>()
		.Select(match => 
		new {username = int.Parse(match.Groups[1].Value), primary_email = match.Groups[2].Value}
		);
		
		foreach (var item in collection) {
		    Console.WriteLine("username: {0}, primary email: {1}", 
		    item.username, 
		    item.primary_email
		    );
		}
	}
}