The letter grade

Problem

The school hands out grades as letters: 90 and up is "A", 80 to 89 is "B", 70 to 79 is "C", 60 to 69 is "D", and under 60 is "F". Return the letter that score earns.

Every line belongs to the group above it: 90 is an "A" and 89 is a "B".

Examples

• 95 → "A"

• 83 → "B"

• 71 → "C"

• Failing

  42 → "F"

Besides these, the challenge has hidden tests that are revealed when you submit your solution.

You start with this

def letter(score):
    pass

function letter(score) {
}