#include<stdio.h>
void main()
{
int score;
printf("请输入成绩：\n");
scanf("%d", &score);
int n = score/10;
switch (n)
{
case 10:
case 9:
printf("A\n");
break;
case 8:
printf("B\n");
break;
case 7:
printf("C\n");
break;
case 6:
printf("D\n");
break;
default:
printf("E\n");
break;
}
}