using System;
public class Test
{
public static void Main()
{
Console.WriteLine("Enter Mark");
int mark = int.Parse(Console.ReadLine());
if (mark >= 90 )
{
Console.WriteLine("A");
}
else
{
if (mark >= 80)
{
Console.WriteLine("B");
}
else
{
if (mark >= 70)
{
Console.WriteLine("C");
}
else
{
if (mark >= 60)
{
Console.WriteLine("D");
}
else
{
Console.WriteLine("F");
}
}
}
}
}
}
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