Solution.cs

using System.CodeDom.Compiler;
using System.Collections.Generic;
using System.Collections;
using System.ComponentModel;
using System.Diagnostics.CodeAnalysis;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Runtime.Serialization;
using System.Text.RegularExpressions;
using System.Text;
using System;

class Result
{
    public static List<int> gradingStudents(List<int> grades)
    {
        for(int i = 0; i<grades.Count; i++) {
            var grade = grades[i];
            if(grade < 38)
                continue;
            var mod = grade%5;
            if(mod >= 3)
                grade += 5-mod;
            grades[i] = grade;
        }
        return grades;
    }

}

class Solution
{
    public static void Main(string[] args)
    {
        TextWriter textWriter = new StreamWriter(@System.Environment.GetEnvironmentVariable("OUTPUT_PATH"), true);

        int gradesCount = Convert.ToInt32(Console.ReadLine().Trim());

        List<int> grades = new List<int>();

        for (int i = 0; i < gradesCount; i++)
        {
            int gradesItem = Convert.ToInt32(Console.ReadLine().Trim());
            grades.Add(gradesItem);
        }

        List<int> result = Result.gradingStudents(grades);

        textWriter.WriteLine(String.Join("\n", result));

        textWriter.Flush();
        textWriter.Close();
    }
}