Grading

Per works at the KTH Royal Institute of Technology, and thus grades a lot of exams each day.

The grading process is rather simple. First, you define five grading limits $a$, $b$, $c$, $d$ and $e$. At least $a \% $ of the exam score is required to get an A grade, at least $b \% $ is required for a B, and so on, and $e \% $ is required to get an E. If you get less than $e \% $ you get an F.

Per’s management has recently complained about a lot of mistakes that Per made during grading, so they want you to construct a program to help Per grade exams.

Input

The first line of the input contains the five integers $a$, $b$, $c$, $d$ and $e$ ($100 \ge a > b > c > d > e \ge 0$).

The second line contains a single integer – the exam score in percent of an exam Per is currently grading.

Output

Output a single letter A-F – the grade of the exam Per is currently grading.

90 89 70 60 50
40

F

100 99 98 97 96
97

D