using System;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Current Level: " + CurrentLevelByExperience(6000));

    }

    private static float NeededExperience(int level, float experienceRatio = 100F)

    {

        float neededExperience = ((level - 1) * experienceRatio) * level;

        if(neededExperience == 0F)

            neededExperience = experienceRatio;

        return neededExperience;

    }   

    private static int CurrentLevelByExperience(float currentExperience){

        float baseExperience = 0;

        int probeLevel = 1;

        do {

            float requiredExperience =  NeededExperience(probeLevel);

            baseExperience += requiredExperience;

            Console.WriteLine("Level " + probeLevel + ": " + (baseExperience - requiredExperience) + "~" + baseExperience + " (" + requiredExperience + ")");

​

            if (currentExperience < baseExperience){

                return probeLevel;

            }

            probeLevel++;

        } while (true);

    }

}