07. Sums Step 3

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace _07.Sums_Step_3
{
    class SumsStep3
    {
        static void Main(string[] args)
        {
            int numCount = int.Parse(Console.ReadLine());

            int num;
            int sum1 = 0;
            int sum2 = 0;
            int sum3 = 0;

            for (int i = 1; i <= numCount; i++)
            {
                num = int.Parse(Console.ReadLine());

                if (i == 1 || i % 3 == 1)
                {
                    sum1 += num;
                }
                else if (i == 2 || i % 3 == 2)
                {
                    sum2 += num;
                }
                else
                {
                    sum3 += num;
                }
            }
            Console.WriteLine("sum1 = {0}\nsum2 = {1}\nsum3 = {2}", sum1, sum2, sum3);
        }
    }
}