Grading
Assume each homework yields a judgment scored as:
- PERFECT = 3
- GREAT = 2
- GOOD = 1
- MISS = 0
Let $n$ be the number of homeworks. Max score = $3 \times n$.
Achievement (percent):
$$ ach = 100 \times \frac{\text{score}}{3n} $$
Grade by achievement:
- A+: $ach \ge 97$
- A : $90 \le ach \lt 97$
- A-: $85 \le ach \lt 90$
- B+: $80 \le ach \lt 85$
- B: $75 \le ach \lt 80$
- B-: $70 \le ach \lt 75$
- C : $60 \le ach \lt 70$
- F : $ach \lt 60$
Input
One judgment in full uppercase per line, each exactly one of:
PERFECT, GREAT, GOOD, MISS.
Output
The grade.
Sample
Input
PERFECT
PERFECT
GREAT
GOOD
MISS
PERFECTOutput
C