#include <stdio.h>
int main ()
{
float score;
scanf("%f",&score);
if(score>=90)
printf("成绩等级为A\n");
else if(score>=80&&score<90)
printf("成绩等级为B\n");
else if(score>=70&&score<80)
printf("成绩等级为C\n");
else if(score>=60&&score<70)
printf("成绩等级为D\n");
else if(score<60)
printf("成绩等级为E\n");
return 0;
}