using System;
using System.Collections.Generic;
using System.Text;
namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine("请输入成绩:");
int mark = Convert.ToInt32(Console.ReadLine());
mark = mark / 10;
switch (mark)
{
case 9:
Console.WriteLine("A");
break;
case 8:
Console.WriteLine("B");
break;
case 7:
Console.WriteLine("C");
break;
case 6:
Console.WriteLine("D");
break;
}
}
}
}