Not big issue just curious about warning in C#

//take user input and make it into a isosceles triangle
using System;
namespace Course
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Enter how tall you would like you triangle to be (Number Ex. 1,2,3,4...)");
            string userInput_string = Console.ReadLine();
            int userInput_int = Convert.ToInt32(userInput_string);
            for(int row = 0; row < userInput_int; row++)
            {
                for(int space = userInput_int; space > row; space--)
                {
                    Console.Write(" ");    
                }
                for (int symbol = 0; symbol <= row; symbol++)
                {
                    int remainder = symbol % 2;
                    if(symbol == 0)
                    {
                        Console.Write("#");
                    }
                    else if(remainder == 1 || remainder == 0)
                    {
                        Console.Write("##");
                    }
                    else
                    {
                        Console.WriteLine("ERROR");
                    }
                }
                Console.WriteLine();
            }
        }
        
    }
}