The answer is correct, but it returns an error. Why? Maybe I did not understand the condition of the task correctly, or can the data be specified for which this code will produce the wrong solution?


using System;

namespace ConsoleApp30
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            int x = 0;
            string[] shoplist = new string[n];
            for (int i = 0; i <n; i++)
            {
                shoplist[i] = Console.ReadLine();
            }

            for (int i = 0; i < shoplist.Length; i++)
            {
                for (int j = i + 1; j<shoplist.Length; j++)
                {
                    if (shoplist[i] == shoplist[j])
                    {
                        x++;
                        i++;
                    }
                    else
                    {
                        continue;
                    }
                }
            }

            Console.WriteLine(x);
            //Console.ReadKey();
        }
    }
}